...
Initial conditions are the starting values in the domain. The closer the initial conditions are to the result values, the less time the simulation will take to solve. You should have an idea of what values you’re expecting but if you don’t know or don’t care to estimate them, you can leave the default values as is. Expand the Initial conditions section by clicking the plus sign in a box on the left. I haven’t tried changing Gauge pressure, since the average pressure throughout the domain is probably close to zero. For velocity, most of our simulations were run at 20 m/s. This means that a lot of the domain will have air moving close to a speed of 20 m/s, with some regions that will have faster air and some other regions with slower air. So I use an initial velocity of -20 m/s in the z direction. For κ and ω, there are ways to estimate these values that can be found online. The values I found were 0.303 m2/s2 and 2.871 s-1.
| Expand | ||
|---|---|---|
| ||
|
Boundary Conditions
Boundary conditions are conditions that stay constant during the simulation. Every surface needs a boundary condition to solve the system, so we’ll create 6. Create a Velocity inlet, a Pressure outlet, 3 Walls, and a Symmetry condition.
...
| Info |
|---|
It should be noted that, like the initial conditions, there are default boundary condition settings. These aren’t explicitly shown but running a simulation without assigning a boundary condition to a face will cause that face to be treated as a no-slip wall. |
Advanced
...
Concepts and Numerics
Advanced concepts probably aren’t needed for now.
Numerics is another section that I would consider as advanced settings. The defaults are selected to work for a broad range of simulations, and you shouldn’t need to make changes often.
...
Simulation control is where we tell the program how long to run the simulation for, along with a few other things. An End time of about 1000 s is usually goodokay, for a lot of simulations I used 750 s or 800 s to get results faster. The Write interval can usually be matched to the End time, unless you want to see the results at multiple time points. 2e+4 s or 2.5e+4 s should be fine for the Maximum runtime. If it takes a little longer, that’s also fine. I have always used Potential flow initialization, as I have had simulations diverge frequently without it. With that being said, I tested this feature a while ago and I’ve changed several things have changed since then so it may not be needed anymore. The rest of the settings can stay as defaults.
...