The ANSYS 3D Design family of products enables CAD modeling and simulation for all design engineers. Since the demands on today’s design engineer to build optimized, lighter and smarter products are greater than ever, using the appropriate design tools is more important than ever.
Two key tools helping design engineers meet such demands are ANSYS Discovery AIM and ANSYS Discovery Live. ANSYS Discovery AIM seamlessly integrates design and simulation for all engineers, helping them to explore ideas and concepts in greater depth, while Discovery Live operates as an environment providing instantaneous simulation, tightly coupled with direct geometry modeling, to enable interactive design exploration.
Both tools help to accelerate product development and bring innovations to market faster and more affordably.
Join PADT’s Simulation Support Manager, Ted Harris for a look at what exciting new features are available for design engineers in both Discovery Live and AIM, in ANSYS 2019 R1. This webinar will include discussions on updates regarding:
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I was on the gondola up at Keystone for night-skiing a week ago, after a long day at Beaver Creek, because the last thing I am going to do at 3:00 pm is try to make it back to Denver, as everyone knows it’s hardly more than a parking lot at that point. As it gets later, there’s nothing like a solo gondola ride, however, a solo ride would stop this story right about now.
On the gondola, I overheard a conversation where one gentleman was discussing how he was unable to open the hatch of his vehicle when his skis are in his roof rack. That’s fair, I know older WRX wagons with the spoiler would not be able to open with skis on the roof no matter what, so I figured that was the case. It turns out, that was NOT the case. The reason his hatch would not open was that he orients the skis with the tails forward because it is ‘more aerodynamic’ that way… I was skeptical, but held my tongue, knowing that I had the tools at my disposal to investigate!
I decided to make a model that would allow me to simulate various conditions to get to the bottom of this. My initial hypothesis is that the addition of the ski rack and crossbars is what has the largest effect on aerodynamics, and orientation of the skis probably has a negligible effect after that. As a side note, I am solely concerned with aerodynamics in this case, and am not worrying about the amount of the ski’s base material that is exposed for a given orientation. I am of the mindset that tree trunks and hidden rocks on the mountain are more of a danger to your bases than small rocks on the highway anyway. If you are waiting to comment, “Just get a roof box!”, I understand as I own both a box and a rack at this point, and they both have their advantages, and I will not be exploring the aerodynamics of a box…
I was able to start by finding some faceted geometry of a Subaru Forester online (I’m from Colorado, can you tell?) and was able to import that into ANSYS Spaceclaim. Once in Spaceclaim, I was able to edit the faceted geometry to get nice exterior panel surfaces, which I then combined to get a single clean faceted exterior for the car.
After that, I used Spaceclaim to generate the remainder of the rack and skis, including crossbars, a ski rack, and a pair of skis (Complete with the most detailed bindings you have ever seen!). I made a combined part of the crossbars, rack, and skis for each one of my orientations, as this allows me to report the forces on each combined part during the simulation.
For the simulation, I used ANSYS Discovery Live, the newest tool from ANSYS that allows for instant and interactive design exploration. This tool lets me actively add my CAD geometry and shows results in realtime. I was able to start with just the car and then add and swap my ski/rack geometry with simple button clicks. With traditional simulation tools, I would have needed to create a mesh for each one of these cases, analyze them one at a time, and the post-process and compare results after the fact. After launching Discover Live, it’s as easy as selecting the type on analysis I want to run.
Once I have selected ‘Wind Tunnel’ for my solution, I can select my geometry, and then am prompted for the direction of flow, as well as selecting the ‘floor’ of my domain. Once that is done, results show up on the screen instantly. I only needed to modify the flow velocity to ~65 mph. I am most interested in the force on the faces of the combined crossbars, rack, and skis in each orientation, so I created Calculations for each one, which is done by simply selecting the part and using the popup toolbar to create the graph.
I was already off and running. I ran each one of the cases until the force plot had become steady.
Seeing that the force results for the Tips Forward vs. Tails Forward cases were very similar, I decided I should also run a ‘Bases Up’ Orientation, even though I STRONGLY advise against this, as UV wrecks the base material of your skis/snowboard.
In addition to the contour plot shown in the images above, you can also use emitters to show streamlines and particle flow, which also give some pretty neat visualizations.
The graph plots show values for the Total Y Force for Tips Foward, Tails Forward, and Bases Up orientations to be 37.7 N, 39.1 N, and 37.1 N, respectively. Using Discovery Live, I was able to quickly run all 3 of these simulations, showing that there is not a major difference in the forces on the ski rack between the three orientations. So, put the skis on the roof in the direction that makes life easiest for you, and keep those bad boys paired to protect your bases from the sun, because splitting them isn’t going to help with aerodynamics anyway!
Next steps would be taking a specific case and running in 2D, then 3D, in ANSYS Fluent.
Below you can find some of the most frequently asked questions from this webinar, along with our answers.
Q: What computer and license type are you actually using for running the simulation? Ram, cores, CPU, etc.
A: 16 GB RAM Intel i7, NVIDIA Quadro K1100M
Q: Is the solver running a transient solution in the background while you are post processing and haven’t paused it, or is it marching towards better convergence of a steady state solution?
A: The solver is running a transient solution the entire time. The only time it is not doing this is if I pause the simulation.
Q: Does this require 3D models to be built within Discovery Live, or it can import outside 3D models (Solidworks etc) and still allows the user to add/modify geometry objects on the fly within Discovery Live?
A: Yes, you can import any CAD native format or neutral format in Discovery Live. You can also create Geometry from scratch in Discovery Live using the SpaceClaim tools.
Q: It looks like when you change the “speed – fidelity” setting, the solver resets; while when you change other settings (like domain geometry), the solution continues from last step. What’s being changed when you change the “speed-fidelity” setting?
A: When you change the Speed-Fidelity setting, the computational grid of the domain is coarsened or refined. It is also re-partitioned/parallelized on the GPU cores.
Q: Are there predictive features of simulation, obtaining design suggestions from the end results? Are there inputs for end results to accomplish reverse engineering?
A: Yes, in a sense. Because Discovery Live provides literally “real-time” feedback on design changes, you have design suggestions based on the end results. For reverse engineering in Discovery Live: there are not inputs for end results, but the part you’d like to reverse engineer can be imported (or created) in Discovery Live, and then analyzed in the range of operating conditions to understand it’s performance.
Q: Do you have any control of the mesh? How boundary/layer effects can be checked?
A: Control of the mesh available via the Speed-Fidelity slider bar. Boundary layer effects could be checked using surface integrals of force, but again recall that if you’re trying to finely resolve details such as boundary layer physics, you may need to consider the next level of accuracy which would be Discovery AIM or Fluent.
Thanks to developments made by ANSYS Inc, world class simulation software is now available right at your fingertips. This platform drastically speeds up and simplifies the purchasing process while providing you with all of the information you need to ensure that you make the right choice and select the software that works best for you.
The offerings are divided into three bundles: Essentials, Standard, and Ultimate.
Each of these includes a different group of tools and capabilities, taken from the new ANSYS Discovery family of products, which includes Discovery Live, Discovery Space Claim, and Discovery AIM.
Interested in purchasing today or just learning more about these great offerings?