February 12, 2023 at 3:37 pmShuvo ChowdhurySubscriber
I am calculating particle deposition in a simple 2D turbulent channel flow.
In DRW model , it is said that Instantaneous turbulent fluctuating velocity is calculated from rms fluctuating velocity of the flow , multiplied by a normal distributed random number.
My question is, where do DPM's DRW get this RMS flow fluctuation velocity from? Is there any specific variable for RMS fluctuating velocity?
I am using RSM turbulence model , where we calculate these fluctuating velocities from Reynolds Stress ( sqrt( reynold stress). Am I right?
Do DPM do the same ?
Please Help. I need this information because I have to change one of the flow RMS flutuating velocity near wall region.
February 13, 2023 at 2:39 pmSRPSubscriber
Discrete Random Walk (DRW) model includes the effect of turbulent dispersion on particle tracks by adding a perturbation or a fluctuating velocity component to every track emanating from the injection locations
For more details, please refer to theory guide: 12.2.2. Turbulent Dispersion of Particles (ansys.com)
If you are not able to access the link, please refer to this forum discussion: Using Help with links (ansys.com)
February 14, 2023 at 8:38 am
February 16, 2023 at 8:54 amSRPSubscriber
The local rms value of fluctuating component is taken from the kinetic energy of turbulence.
February 16, 2023 at 11:00 amShuvo ChowdhurySubscriber
Hello SRP , Thanks for the reply .
Turbulence model like k-e and k-w, where isotropic turbulence fluctuation is assumed, these fluctuating velocities is calculated as sqrt(2k/3).
But, since the RSM model which allows anisotropic turbulence fluctuation , will it be applicable too?
February 16, 2023 at 12:46 pmSRPSubscriber
Yes it is applicable but fluctuating velocity is multiplied by the extra term when RSM model is used.
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