Introduction to Autodesk CFD Integration with Inventor

DAVE GRAVES: Well, good morning, everyone. Thanks for getting up early today. Appreciate it. My name is Dave Graves. I'm a subject matter expert. I've been working with the CFD product for, gosh, over 15 years. I was part of Blue Ridge Numerics, who Autodesk acquired about seven years ago. I actually was not part of the acquisition, managed to come in a year later. So I've actually done a lot of other things at Autodesk. I've worked with manufacturing solutions. I worked with Fusion, and now I'm back on the CFD team.

Just on a total side note, if you guys are interested, a colleague of mine are doing a little e-publication. And feel free, follow me on Twitter. Send me an email if you want a copy. It's really lightweight. It's just this idea of really upfront simulation and I guess some common mistakes we see people make.

I don't mind questions, so if you have a question as I'm going along, feel free just to raise your hand, shout it out. If I can answer it in context, I will. If I have to put it at the end, we'll save some time. And worst case, I'm here all week. We can dig a little deeper.

What I want to talk about today is I'm going to start really, really high level and just talk about what CFD is, what's involved in the process. I'm going to give you some tips and tricks for Inventor, many of those using Fusion. You can feel free to talk to me as well. There's some tips and tricks there after I can share with you. I'm going to try to spend as much time in product as I can. And then hopefully we'll have some time for questions at the end.

So the first thing, I know this is real simple. It's how I explain it to my wife. You know, what is CFD? Basically it comes from the C, Computational. It's a big calculator. Fluid being a liquid or a gas, air, water, fuel, peanut butter, blood, all these things. And then the dynamics is the movement of it. So how is the air moving through the room? How is dog food moving through a die? How are liquid moving through heat exchangers, those type of things?

And then almost all the CFD codes on the planet have thermal capabilities, so electronics, cooling, heat exchangers, things along that line. And what it lets you do is it lets you actually create a virtual wind tunnel, flow bench, or thermal test rig. So the idea is, you can explore all these ideas before you actually physically test them. So that's kind of the idea behind CFD.

We are a general purpose tool. So the thing is we do almost everything under the sun. What's exciting for me is when you talk about things we haven't done so we can try to figure out approaches for it. But valve is a common one, heat exchangers, pumps. I think we have some pump people here today. We've done things in the medical industry. If you're in the booth out in the show, there's a really neat external area. There's an IndyCar in there that we've done some studies for, kind of combining CFD and virtual reality. So check it out. Electronics is a big one, blowers and fans. And then we also do a lot of stuff in the-- excuse me-- architectural industry. So ton of different things. If you have any sort of liquid or gas moving in any thermal constraints, there's probably a need for CFD.

Some of the common misconceptions-- I've been doing this for a long time. A lot of people still think that I need a specialist in my company. I need someone that just does CFD. I need someone with a PhD level. I like to joke, the only initials after my name are D-A-D instead of anything fancy. I don't have an advanced degree. I just understand the basics of my problem.

And we find is most of the designers, most of the engineers in these companies know what makes a better product, and they understand the basic of what their product is doing. As long as you know that, then you should be able to leverage the CFD product to make a better product. People think it's only for large companies. You have to invest in all this hardware. And that can't be farther from the truth. A lot of companies, including us, we offer cloud solving. We run on hardware that runs Inventor. So don't worry about needing these super high-end machines.

And then people-- again, there's this stigmatism where you think you need to be an expert to understand the results. And again, the visualization tools are so easy, you can tell right away, is my design better or is it worse, where are the problem areas, and you can try some innovative fixes.

And then I see a lot of people doing this. They say, well, let me just do CFD on my final design and just use it as a validation tool. Again, that is so far from the truth. The earlier you can use it, the more insight you can get. It's like all the other things. The earlier you can get insight into your process, the more successful you're going to be. You've all seen that curve, right, where the longer you wait to make a design change-- I like to say the auto industry is a great example. When there's a recall or something, it gets super expensive. So the earlier you can find issues, the more beneficial it's going to be.

So the basic process-- doesn't matter what type of simulation you're doing-- is going to follow these basic six steps. The first thing, it's going to be important to define your problem. And I was going to recommend if you're new, start simple. What's really the problem? Do you want to get a lower temperature? Do you want to get a lower pressure drop? Do you want to get even flow distribution? So don't think of it as the problem of this whole ginormous system. Just think about what's going to make my design better. Are there minimum constraints? Do I need to maintain a certain flow rate? Do I need to keep everything under 50c? Think about that.

And then these are the most common steps. We're going to start with geometry. The CFD tool will run native geometry. So it's actually taking your true geometry and meshing it and coming up with a solution. Then you define the materials. You set your conditions. And then basically, you tell the software what you want to solve for. Is it flow only? Is it thermal only? Is it couple flow, radiation, all that stuff? And then you run the software, and you get a solution. 42, right?

But the beauty of it is, what happens if I go back, and I make a change to my geometry? What if I change my material? What if I try some different things? How can I get a better design?

I always like to talk to engineers and say, what do engineers do in general? Anybody? Designers, what do you do? Solve problems? Right? That's the fun part of it. I come up with solutions. When your boss comes to you and says, hey, can you solve this problem, how many guys just have one idea on how to solve that problem? How many people have multiple ideas, 4, 5, 10 different ideas? Does that make sense? How many do you usually test? One? Right? You guys are under pressure. It's like, I'm going to intuitively go with the one I think is the lowest risk, right? The idea of simulation is you can explore those ideas, and you can, again, just open it up and try things maybe you wouldn't prototype, because the cost is minimal, just a little extra time. So just think about that.

So today, the biggest challenge with our CFD tool, to be honest with you, is-- and it has been for the last 15 years-- is geometry. We're doing some really cool things to fix that. But today it's still kind of the first thing you need to do. As an example, this is a little smart speaker design. Doesn't matter if it's a valve or whatever it is. The challenge is there's a lot of unnecessary detail in here. I have screws here. I have detailed components for the header in here. I could have some sheet metal with some small gaps, production-level geometry. Does that make sense? And the problem is, in theory, you could solve this in CFD and so forth, but as you add that complexity, it really increases your runtime significantly, and you don't get very different of an answer. All right? So there's some more detail up there.

So the idea is why don't I just keep the key detail I need. So an example, this speaker is a little simplified. The hardware is gone. These are some simple sheet metal parts, right? And then this is going to run in my CFD tool. Part of it goes back to, too, that little bullet about waiting for the final design. If you wait for the final design, it gets harder to do this. So earlier on, do some basic concepts, and you'll be much more successful. But here, I mean, some tools, the components are primitives, and it just runs a lot easier.

So I'm going to show you a couple tips and tricks on how to do this in Inventor, OK? A couple of basic techniques. This first one-- let's see if this video plays. Yeah, here we go.

This first one is-- we deal with sheet metal a lot, especially in electronics, telecommunications, that sort of type thing. There idea is let me just recreate something. OK, so I'm in Inventor. I'm creating a new part in Assembly Mode. And I'm basically going to leverage-- use the existing geometry, project it, and create a box. I like to use the edges, because now it's associative. So if I make my box bigger or make it smaller, whatever I create is going to stay parametrically related to it.

But all this is is a simple box I'm going to snap it right to the other line. Any minute now. And shell it out. Because in reality, that's what a sheet metal box is. It's just a rectangular shell, right? I'm going to ignore the corners. I'm going to ignore the little gaps in there, because they don't tremendously impact the results.

And then, as another example, I can-- there's cutouts for the connectors here. So again, I can just leverage the existing geometry, that front panel, just project it again, and just extrude those cuts. Does that makes sense?

So sometimes people will make a copy of their production geometry. It's probably the best thing to do, because the simulation, you're going to, for lack of a better word, probably have to hack up your geometry. So you probably don't want to mess with anything that's in production. And there we go. I have my box with my connectors in it.

Really helpful. Sheet metal fans and blowers. A fan or blower in CFD can be represented as a cylinder. So you don't want all the blades, I mean, and everything like that. PCV components can usually be cubes or cylinders. You're going to get the same results. So these are some common things where you just kind of sketch over that existing part.

Another idea, another way is to actually simplify the existing geometry. There's pros and cons of this. Same sheet metal box. There are a couple of features in Inventor I would use. One is Delete Face. You guys use Delete Face at all? Anyone? A little bit? The important thing is-- you'll see when you do this-- is make sure you check on the heal geometry. Otherwise you get these surfaces you can't do anything with it. So that's a simple one for some fillets and things like that. Holes works really well.

And then the other thing is using some of the direct editing. So if you use the direct editing-- we'll get to it in a second. I'll even show you that end product. But you get to the direct editing, when you delete a face or you delete a surface, it actually auto heals for you. So I use the direct editing to, you know, again, fix some of those holes. I use it to maybe, if I have a gap, to snap surfaces, to fill a gap, things like that. Use the Move Face as well so it slides the whole face. So you guys use much of that, the direct editing in Inventor? I mean, you probably don't have a big use for it, but for simulation, it comes in super handy. And you'll see I'm going to delete these faces and just manually, you know, get rid of this whole kind of corner here. So it's a little bit more work, but you get very similar results.

Let's see if this works here. You get a nice little preview as you're going through here. There we go. Only took 17 clicks. Now basically, I made a sheet metal-- I made a box that was shelled. So same sort of typing. So those are the two basic techniques, modify existing or just create something new on top of it. I'm probably going to pull these edges out to snap it. So that's that Move Face. There it is. Questions? Anybody have any questions? Yes, sir.

AUDIENCE: Would it make sense to utilize a shrink wrap?

DAVE GRAVES: Yes, shrink wraps can be handled, because it'll merge some of the parts together. You can clean them--

AUDIENCE: [INAUDIBLE].

DAVE GRAVES: Mm-hmm. Yep. Absolutely.

So another thing with CFD and geometry, it's that fluid part, that flow part. There are two main types of flow, internal flow and external flow. For external flow, we actually have the ability in CFD to create a box. I think it's just easier to do in Inventor. So in example, if I'm going to do flow on the outside of this smart speaker, it's just a cylinder. This is some external arrow for a bike, for a cityscape, for a car. The idea is just a box. You want it to be 5 to 10 diameters in front of it so flow fully develops.

But it's really simple. If I want to do a wind study as an example, this is a box. I create the box. I just rotate it to a different angle. So I just like that. It's super simple in Inventor. It's just the easiest way to do external flow. Does anybody do external flow? Awesome. Yeah, so it's super simple. Talk later, but if you guys have collections, you can take the CFD results directly from CFD and [INAUDIBLE] in CAD and take those wind results and look at deformation and things like that. Super simple to do.

And then the next thing is a lot of flow is internal flow. Again we have the ability to do this in product. I'm saying it's much easier to do in Inventor. So the idea is that if you create airtight/watertight geometry, the CFD tool will fill in the negative. So you don't have to do any Booleans. You don't have to do any sculpting, picking all these surfaces. And I'm going to show you an example. We're going to make everything watertight. Much like external flow, people kind of get a little bit confused. So in this valve up here, this blue part is-- I call it a flow extension. So I make it longer just because of the nature of fluid dynamics. A flow needs a little bit of space to fully develop. But what I do in the tools, I make those parts the same working fluid, whether it's water, air, blood, et cetera. So again-- and I'll show you how to do this in Inventor. It just makes it a lot easier, makes your solution a lot more stable. But it's this idea of creating watertight geometry.

All right. You guys had enough PowerPoint? Maybe? I can go more. I can-- no.

So I just want you to remember this process, OK? This is what we're going to do. We're going to define a problem, do some things, bring in some Inventor geometry, go through this whole process. All right? So here we go.

So first thing I want to do is define the problem here. So this is a faucet all right and the idea is that we have this new mixer that we want to introduce. And the goal of this mixer is to make sure when I put my hands under the faucet, one hand's not hot, and one hand's not cold. It's nice-- evenly distributed. Does that makes sense?

What else might I be concerned with? Anything? So temperature distribution. What else is maybe a concern? It's got to work in a residential application. Pressure drop, right? I got to be able to-- I don't need like 10,000 psi water, because that'll just blow up my pipes, right? So those are the main things we're concerned with. We really want to make sure we get a good mixing and a lower pressure drop. Makes sense? All right.

So define our problem. The next thing is geometry. So I want to show you something about this model, which is pretty typical. This is maybe on a production model. I have some gaskets in here, right? There's a slight gap here for clearance. I have some threads, so I could thread this handle onto the valve stem. Does that sound reasonable? Right? Really bad for CFD. OK? Really bad.

So a couple of things. The first thing I can do is get rid of these gaskets. Come on. All right. I can delete them. I can suppress them. And sometimes hiding works. Hiding is a little iffy, so-- what's the challenge if I delete something?

AUDIENCE: Then you have to put it back.

DAVE GRAVES: We have to put it back. But even with parametric modeling, what could be a challenge?

AUDIENCE: [INAUDIBLE].

DAVE GRAVES: Any relationships, right? So deleting can be a pain. So suppressing might be something easier. You create a level of detail. This one has no references, so I'm going to delete it. But just kind of be aware. It depends on your model and how you're-- but again, the longer you wait to do this, the more relationships you have, right?

All right, so let's go to my section view again here. I'm not sure why it disappeared. So I got rid of my gasket. Now I need to-- I want to close up this gap, and I want to get rid of these threads, right? So let me find it in here. Come on, section view. It keeps dropping out my section view here. Let me hit the checkbox again. All right.

So if I edit this in context just so you can see what's going on here, first thing I want to do is get rid of these threads. So if you haven't used it, I'll use the Direct Editor, and I'll choose Delete. And what I like about this is as I'm building this, it's going to give me a visual. So I can say, oh, that's what I want, and then I check it out. So now I got rid of all those threads. It's just a simple stem, right? Same thing for where the gasket was. I don't need this. So I can do the same sort of type thing. I can delete this here. Right?

And then the nice thing about the direct editing is that one of the advantages, I don't have to go through a feature tree and find-- like, there's a slight gap here. I could find that feature, find that Revolve, change that dimension, which is OK, or I could just say, you know what, I just want to move this. I just want to resize this and make it line the line. So if I do this-- does that make sense? Close that gap off. Get rid of my threads. Direct editing, it's nice. It doesn't affect anything else in my tree. So I've got that.

And now the next thing, I want to do the same thing with my handle. I like to do things in context, editing context, so I can see it live. So this one, we're going to do something slightly different. I'm actually going to go to the Delete Face. So what do I need to do when I delete face? What's the main thing I need to do when I select this? Heal. Yep.

So I get extra faces here. Not a big deal. I can just do the same thing here. And voila.

Now minor problem. What is it maybe the minor problem that's left here? Interference. So by the way, with CFD, interference isn't always a bad thing. What it's going to do is create three parts, one for the handle, one for the valve stem, and then one for the interference. So it's not a huge deal.

But if I want to get rid of it, this is something I do. There's probably different ways to do it. But what I can do is Copy Object. So I'm still editing that handle. And I like to use a composite. So I copy the object. And then I go to Sculpt, and I cut away that surface right there. Now it's the wrong side. So I flip it. Oops. Hold on. Try this one more time. There we go. And now I have no interference. Makes sense?

All right, so I have closed off-- got rid of all my unnecessary detail. I've closed off any gaps. You kind of saw the earlier slide with-- what do I need to do now? Is anybody paying attention? I want to make my caps to make my internal flow. Super simple. What I'm going to do is I'm going to create a component in context. I could call this outlet cap. Don't need a Z there.

And I'm just going to use this sketch, this plan, as a reference. And then again, 2D sketch. Again, what I can do is project geometry. You don't have to. You could do a sketch. I just like to do the project geometry so it's associative. Make it bigger, smaller. It's going to keep up with it. And then I just extrude it. And I have a cap.

Now, FYI, I did the ones on the bottom already. I don't think you need to see me do that twice, right? So now my geometry is watertight. I'm ready to launch in the CFD.

Up here in the Simulation tab, there's a couple different options. So this first one, Model Assessment, these are some tools we've added, because we know geometry is a thing. What it will do is it'll bring the model in. It'll look for gaps. It'll look for slight, small interferences. It'll look for potential problems and identify for you. So if you're not sure, you're having trouble, you can launch in the assessment tool to provide you some guidance.

The next thing we can do here is something called CAD entity groups. What I can do is actually kind of tag some things in Inventor. As an example, I could say, let's do-- let's maybe identify my outlet. All right? And I could say OK, outlet-- let me just make that my outlet. Does that make sense?

And then I could say, all right, let's do inlet. You can do solids or volumes, or you can do surfaces, depending upon what you want to do with them. OK, here's my inlet. And I can select these two surfaces. So you'll see, when they come into the CFD application, they will have some of that identified. And I'll show you some things you can do with it.

We also have the ability to work with iParts or iAssemblies. Little lengthy to show, but if you wanted to run through a bunch of different scenarios, you can link them to your iAssemblies, and it would automatically do some things for you. So it's a little more advanced, but the capability's there.

But when I'm ready, I'm going to launch the active model. We'll call this AU faucets. And again, we bring in the true geometry, bring in every single part, all the curvature, and everything else. And you're going to see when this comes in, there's a button right here, or a text that says "one additional part created." Basically, that's this part right here, which is the internal. Right? So we made the geometry watertight. We filled it in. So easiest thing to get geometry.

Remember the first-- we had define problem, geometry. You guys remember the next step? What was it? Materials. Yeah, just got to make sure you guys are paying attention. Right? So it's going to be materials. Which if you come in the ribbon, the idea is we're going to guide you through the process. So materials is the first one there. A lot of ways to select material. I can draw a box.

So just an interesting thing-- let's remove all here. Interesting about CFD that may confuse you with Inventor and other products, if I want to select multiple parts at the same time, what do you do in Inventor?

AUDIENCE: Control.

DAVE GRAVES: Control, right? Control. I don't need to do Control. I can just kind of pick at will, and it automatically does. So when you start seeing that, be aware. You don't have to use control. But what I'm going to do is just select everything. So do a box select. I can select out of the feature tree. If you notice, all these names came in. They're directly from Inventor. We'll talk about rules. If you're doing common assemblies or common simulations, you can set up rules for it.

But what I'm going to do is start off making everything stainless steel. And then I can select multiple parts. Here's a little-- so this is a tip that I do that maybe is not in our Help. I select everything. And then an example is, these handles, do they affect my flow very much? No, they're outside the flow path. Do they affect thermal very much? Probably not, because they're really far away from the thermals, right, and it's probably ABS, so not even that much of a deal.

So what I can do is suppress them from here. So you still see them visually, but when the model runs, it's not going to be part of the solution. OK? And then maybe my mixer, maybe it's copper. Make sense?

And what am I missing? What material am I missing? Water. Right. So if you notice I build this, the legend here, as I see it so I can see if it's right or wrong. So let's see here. Make this water. By the way, you are more than welcome to create your own materials. So let me open this material dialog box up.

So a couple of things, the two most common materials are fluids and solids. Now if I wanted to create my own as an example, when I click Edit, everything is grayed out. We don't let you edit our materials. So all you do is you create either your own database, or you create a local material. Then you can edit it. And we can vary properties by all sorts of things. Don't have to be constant. So just kind of be aware. You have to make your own kind of material database to edit something.

But fluids and solids. The next thing, most common one, is a resistance. Think of an air filter. Think of a perforated plate. You have like 200 holes. So rather than model 200 holes, you could say, well, this is 50% open. This is 25% open. I have a flow curve, something like that. So it's taking something really complicated and reducing it down to something that mathematically is pretty easier to resolve.

Same thing with fans and pumps. You don't want a model-- we actually have the ability to take a fan blade and spin it, but it takes a long time. So if you have-- you're using a fan, you have a fan curve. You can put that in. We'll tell you where on the curve it's going to operate, which is probably the most important thing. Same thing with a pump or a blower. No one uses check valves, but it's still in material. You could have something open and close at a given rate. We do things with electronics for a printed circuit board. You put in the copper information, the layer information. We'll do a lump sum value. We'll vary the conductivity based upon direction of the orientation of the board.

Compact thermal model and LED for electronics, lots of times they'll give you a Theta-JB and Theta-JC, junction and board temperature. So we can calculate that. It's a simplified material. A lot of people use-- does anyone use thermal or text, thermal electronic components? It's a crazy feature we have.

And then we just introduced this a while ago called the heat exchanger. Think about it for-- a lot of us for the A/C industry, where it's a heat pump, and there's a certain cooling capacity. There's a certain dehumidification process. So those, again-- taking something really complicated into a very primitive shape. And then anyone doing electronics, we actually have a heat sink material. So if you have a curve from a supplier of a heat sink, you can model it as a box and put that information in.

So I'm just going to stick with fluids and solids here. Any questions? All right. So next thing is-- we used to call it operating conditions. I like that much better than boundary conditions. But we renamed it boundary conditions. So was that last box. Remember it?

And so here's something that's interesting. If you notice, when I-- I created some groups, inlets and outlets. Can you kind of see, they're right here in the feature tree. So what that can allow me to do if I wanted to is I could create a rule. So I have faucet inlet and faucet outlet. And if I click Apply, it actually put those conditions on there. Right? So that's the idea. You can leverage your material information in Inventor. You can leverage those entity groups and kind of automate the setup process. You don't have to, but you can.

People ask-- I know you're thinking this-- do the materials from Inventor automatically map over to CFD? No. The reason is-- I think someday they will. I think in general, there's certain information that we require that's just not in the Inventor database. But what you can do is create a rule. So if it's always stainless steel whatever in Inventor, you can map it over to CFD. So when it comes in, it automatically assigns it. So there's ways to do it. You create it once, but it's not there today.

So looking at this boundary condition, what I've done is I put in a volumetric flow rate of 1 gallon per minute. What's really nice is I can mix and match units. So I can put liters per minute. I can put it-- what's another one? Gallons per hour? So you can mix and match units in here.

The most common boundary conditions are going to be-- wait a second here-- are going to be volumetric flow rate, velocity, mass flow rate, and potentially pressure. Another common mistake I see people doing for incompressible flow is they will put, say, 1 gallon per minute. They add 50 psi and then put 25 psi in another outlet. It sounds really weird, but the software wants to calculate one or the other. So people will over-constrain it and just put too much information. So if you're going to do a volumetric flow rate, a mass flow rate, I like to put-- as an example, in this problem, I like to put the outlet as 0 gauge pressure. Because we were concerned of what? Pressure drop, right? And due to my fine NC State education, I can subtract zero pretty quickly. So it makes it easier for me. But that's generally the thing. We just say it's open atmosphere.

Compressible flow is a little bit different. Those conditions get a little more critical. If I'm doing a pump curve, those conditions get a little more critical. I need to put back pressure and things on it like that. But just for most of the flow, that's what a lot of people I would say do, common.

In this case, I want to do hot and cold water. So maybe an example, I can put my hot temperature at 120 Fahrenheit. I can put my cold temperature Celsius. What do we got here? Temperature. I don't know, 5 Celsius. Make sense?

Let me go through some of these conditions here. So we have-- velocity, mass flow rate, and volumetric flow rate are actually almost the same condition, because all the software does is it takes a look at-- if you do volumetric flow rate, it looks at the density and the area, and it puts in a uniform velocity. If you do mass flow rate, it looks at the same thing. It looks at the mass flow rate divided by the density and area, and it puts in a velocity. Velocity puts in a velocity. So just kind of be aware. They're all very similar conditions.

Slip symmetry-- so the reason it's called slip so you can use it for a symmetric plane. But for external flow, we basically-- you guys remember the big parabolic curve, two walls, in college where velocity at the wall is zero? Right? What slip does is let velocity go along that wall. So it's really good for external flow. So I don't need to model something 2 miles wide. I can make it narrower and let the flow go along the wall. So that's why we call it slip. Same thing. It just removes any wall conditions.

One of the things, if you knew any traditional tools, they make you define walls. Our tool, everything is a wall unless you tell it otherwise. And slip is one mechanism to do that.

Unknown is a condition for-- we use it for compressible flow a lot, where if you apply a pressure to a surface, it's going to try to keep uniform pressure on the whole surface. Unknown kind of lets it float. So it's used for compressible flow a lot. Scalar is used for mixing. We can do heat fluxes and total heat fluxes.

Film coefficient is really good for electronics cooling. We assume the whole solution is fully insulated, [INAUDIBLE]. So if you don't put a film coefficient, it could get too hot. So a film coefficient, it's like some heat's going to go through that wall. So it just lets you kind of control that. And then fan, current and voltage, we do joule heating, which is kind of cool. Those are the basic conditions. 90% of the people will do heat fluxes, volumetric flow rate, and pressure drop. That's what most of the people do.

So I have all my conditions. We're going to run this steady state. We have the ability to do transient. So sometimes people use an initial condition. Everything is at 50 Celsius. Everything is at 75% humidity. And we'll calculate how quickly it changes.

And then we'll talk about mesh. Everyone know what a mesh is? It's OK if you don't. It's basically, we take your model, we break it up into tens of thousands of little pyramids, and that's how we analyze it, right? Easiest way in our tool is just click this automatic size button, and we automatically kind of come up with size. We look at curvature of the geometry. We look at edge length, and we try to optimize it. That being said, I always tell people, start with the defaults. You can always add or change it, but the default-- we're kind of set up to do 80% of the problems the first time. OK?

But if I wanted to, this little mixer here-- if I wanted to maybe add more mesh detail there, I could simply say, all right, let me edit this. And if you see a slider here, it's going to make more mesh, and it's going to propagate out. So you can control it. We can put mesh regions in. There's all kinds of things. But start with the default.

If anyone wants to get real fancy, we actually have the ability to do motion. So if I wanted to, I could take this mixer. I can move it up and down linearly. I could kind of do-- I could have it oscillate. I could do all kinds of things. We also have the coolest thing is something called free motion. We used to joke we were going to predict the lottery. But obviously, I'm still working, so that wasn't successful. But the idea is you could have something bounce around like a ball check valve. You can actually see how that goes around. So these are advanced. They're transient. But they're pretty cool capabilities within tool.

Another thing we have is something called free surface. So I could actually watch this faucet fill, watch the water come out of the faucet. So some other neat capabilities. Any questions? Sometimes I go on and on. So make sure-- all right.

So I'm all ready. I have everything set up. I want to solve this. So this is where the physics come into play or what I want to solve for. By the way, I can solve locally on this machine. I can solve in the cloud. I can solve in any other computer on my internal network that has CFD installed. So there's a ton of different ways to solve, a remote solving, local solving, et cetera.

What do I want to solve for? So in this case, I want to solve for heat transfer. If I want to solve for radiation, it's a button click. If I want to take gravity, they're very simple. Put it in the vector. Does that make sense? So it's very, very easy to say, oh, I want to turn on gravity. I want to do this. But again, remember what you're solving for, start simple. And I'm going to run this live. Make sense? All right.

One of the really cool things I love about this software is that I can interact and post process results while it's solving. I don't have to wait for it to be done. And I half joke when I say this, but occasionally I've been known to set up problems backwards. So instead of waiting for everything to finish, I can kind of see this right away. Let me see what's going on here. All right.

So in a second-- there we go. This is actually the flow solution. A couple of things-- it can be a little confusing. The first thing is when you enter the results, the tab changes. So this is where you get that 42, right? Where do you get the answer?

There's global and planes. And we'll talk about as we go left-- probably global and planes are the two most common places people start. The first thing is global. That's just showing every surface is colored based upon that quantity. So anyone know why the faucet's blue? What was that?

AUDIENCE: It's not moving.

DAVE GRAVES: It's not moving. The velocity at the walls are zero, right? If I change this-- everything is right click, but you can also do it from the menu. If I change this to temperature, now I see the temperature developing, right? Make sense?

What's really nice about this global mode, if you guys look right here, as I move my mouse over this, I'm getting that value at the surface. Right? So how many thermocouples would that take? Right?

That's another thing. You have to do physical testing. You'll always have to do it. But you're limited by how many sensors you have in there and so forth. This is almost unlimited. Again, I can move this over. I want to switch to Fahrenheit. Don't worry about it. It's a right click. So you can set some of these default units. So I get this value, temperature value, anywhere in there.

So the next thing, the most common thing people use are planes or cut planes. Very similar to a cross-sectional view in Inventor. So when I click Add, what it does is it puts a plane down the center, I think normal to the X. What's nice is I can-- I'm going to change this to velocity so you can see a little better. But I can take and slide this anywhere in the model. I could reorient it, move it up and down. So it's really easy for me to get this anywhere in the model. Go to Z here.

So before I was probing on the surface. Now I'm in velocity. As I move my mouse, the same area, I'm getting the velocity. And again, I could change it to any units I want. OK? Make sense?

Now, what was the goal of this mixer? Do you guys remember? What was it?

AUDIENCE: Even temperature.

DAVE GRAVES: Even temperature. OK. So let's take a look at-- so a plane is really-- let's go to the plane. What I can do with plane is turn on some vectors. This is what everyone really likes to see. Let's see what that velocity is doing here. OK? Zoom in a little bit.

So here's my velocity through this mixer. By the way, you can turn things on or off. It's pretty slick. Make this shaded here. Let met edit these vectors. Little too many vectors here. Whoa. [INAUDIBLE] plane. Sometimes we show too many things. A little bit bigger. Little bit space there. So what do you notice about this mixer? What do you see, visually? What was that?

AUDIENCE: It's flowing straight through.

DAVE GRAVES: It's flowing straight through. It's not doing anything. Who came up with this design? Right? But the thing is, what would you get with your test results? Here's what you'd get. I'll show you. Just show you this. Hold on.

If I look at temperature, and I look at my outlet, I get something like that, right? So let me just even give you some more numbers. If you want numbers, by the way, again, cut planes, we use them for a ton of things. What I can do if I really want to dial this in and see what that profile is, I can draw a plane across there, and I can look. I've got what, almost a 10 degree delta on there? By the way, everything I do-- check this out. I hit this button called summery up here. Most valuable part of the tool. Summary is going to put it in a queue that's going to let you compare when you do other things, right?

So if I'm testing, I get a couple of things. I said, OK, I know what my exit temperature profile is, but I don't really know why. Right? Does that makes sense? So by being able to look at the view in here, this lets me know why. Does that makes sense? So again, you don't need to know-- you don't necessarily need to be a PhD in fluid dynamics to know the mixer's not doing anything. Right?

So just show you some other results I can get out of there. Oh, let me add this plane back. Sorry. All right, if I wanted to do some comparison, again, right, I could set this up. This is kind of a good one. Let me do summary. I can see there's no mixing in there. If I wanted to look at the pressure drop, another thing I can do is just change this global result to pressure. Change my units to psi. And if I just probe here, I can see I have roughly, what, 2 and 1/2 psi here, right? So that's probably OK. 40, 50 psi.