I’ve spent a bit of time putting Virtualwind through the paces. Looks like a winning piece of software. First thing to mention is: Virtualwind is intended for simple CFD studies, pedestrian-level wind for example, not complicated mechanical system studies. Second thing to mention is: it has a SketchUp plug-in…so keep this in mind as well. I’m very interested in this new move by many Building Performance Simulation software developers toward SketchUp as a geometry handler: as troubling as that is in some respects (geometric integrity being one of them), it also shows a commitment to fluid work-flows and intuitive UIs. Two other good examples of this are IES VE‘s SketchUp plug-in (very cool), as well as the new EnergyPlus SketchUp plug-in (buggy, but shows promise). Virtualwind falls in the “very nice” category.
1st: You start in SketchUp, modeling or importing your geometry. For my test, I decided to grab a random building (one I didn’t model) so as to throw something at it that I thought would take some doing, perhaps some massaging. I downloaded the Seattle Public Library (ok, not so random after all) from Google’s 3D Warehouse.
On the SketchUp side, Virtualwind is mainly concerned with parsing the geometry in such a way that is amenable to CFD analysis. This part is awesome. It’s about a 2 click process of checking the model for “water-tightness” then separating the geometry into vw_relative layers. I spent all of 5 minutes figuring this part out.it’s straightforward, and it preserves the original geometry nicely. Next you click the Virtualwind button and it creates a CFD project file and launches the application. What is normally jarring is what happens next: in the case of the IES-VE, you usually are presented with a dramatically more complex interface. Not so here. Virtualwind launched right away with “my” library project loaded and looking perfect, the interface only presents you with a couple buttons.all in order of what should happen.
2nd: In Virtualwind, you do have to go through some steps to setup your CFD study, but these are refreshingly easy and straightforward, all with adequate visual feedback to let you know what is happening. You set up a domain (this is basically a bounding box around the area of the model you want included in the study. You set a wind direction and speed, and this is just a big arrow on the edge of the domain. Next you add/load some atmospheric conditions.and that’s pretty much all I needed to do. In this case, I ran the study with 15 mph wind from the west on a cool day…no context in the model, but I was just testing it.
3rd: You click “Submit Study.” From a technical standpoint, this part was impressive. Virtualwind launches ViNE (their actual CFD simulation engine). So ViNE client launches, which lets you set up single or multi-processors setups, as well as network nodes for processing different time-steps. It was super-easy and sets up a nice job monitor of work in the queue. One you’re ready to start, you just click “Start.” The only thing lacking was an ETA bar, but it does keep track of how long a study needs to run. Just for kicks, I ran the study on high-quality (I figured I had a relatively simple geometry), and it took 1 hour 54 minutes (Intel Core 2 Duo 2.97 GHz) using only one of my processors. When it’s done, it ViNE (the simulation engine) spits out the results back to the Virtualwind interface and lets you view it in many different ways, as well as output animated AVI movies as well. Here’s a screen capture:
Again, I’ve only spent about an hour with the interface and work-flow, but it really looks like there’s a lot under the hood, all while making simple studies relatively painless. It also looks like Virtualwind will accept any STL file (so can by-pass SketchUp with some finesse) but – at this point – the SketchUp plug-in does some nice heavy lifting when it comes to geometry integrity checking.
Overall, Virtualwind is well worth checking out for early design studies.