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nzy102 April 23, 2007 20:06

Hello: I have several quest

I have several questions about perturbU posted in the forum for initializing velocity field of channel flow:

1. do I need to turn on bulk flow?
2. How to choose streamwise and spanwise perturbation spacing? For know, if my channel domain is pi*1(pi/2)(stream wise * vertical * spanwise).
3. I used this perturbation code to initialize the velocity field. Then after running channelOoles for more than 20 flow through times, the calcuated pressure gradient is still way off from analytical solution. Since I can't tell what is wrong with it, I further tested perturbation code using fluent les model. The initial condition is based on perturbU. After I ran fluent after 50 flow through times, I can't see any turbulent structure in instantaneous velocity field. Somehow turbulence has been damped out. Retau for my case is 180.

Anybody here has similar experience?


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