Is it possible to influence the velocity of an scalar transport equation?

jannnesss · January 9, 2010, 19:05

Hey everyone!!

Is there any possibility to influence the velocity of an scalar transport equation. I want to reach the scalar is transportet by another velocity than the flow velocity.
For example: the transported scalar should move with a fix (very small) velocity in the radial direction of a pipe, when the main flow is in the direction of the pipe.
Thanks a lot!
With best regards, Jan

Tristan · January 11, 2010, 13:02

Jan,

What's the physical mechanism here? Can you get the radial advection with a modification to the diffusion coefficient? If you don't want advection due to the flow velocity, it seems like you should use a diffusive transport equation and adjust the diffusion coefficient to get the desired behavior. I know that in turbulent particle-laden flow modelling they talk about particle "diffusion" even though particles don't really diffuse, but their response to the turbulent velocity fluctuations can be treated as a "diffusion".

Tristan

January 9, 2010, 19:05	Is it possible to influence the velocity of an scalar transport equation?	#1
jannnesss New Member Join Date: Jan 2010 Posts: 5 Rep Power: 16	Hey everyone!! Is there any possibility to influence the velocity of an scalar transport equation. I want to reach the scalar is transportet by another velocity than the flow velocity. For example: the transported scalar should move with a fix (very small) velocity in the radial direction of a pipe, when the main flow is in the direction of the pipe. Thanks a lot! With best regards, Jan

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January 11, 2010, 13:02		#2
Tristan Member Tristan Burton Join Date: Mar 2009 Posts: 43 Rep Power: 17	Jan, What's the physical mechanism here? Can you get the radial advection with a modification to the diffusion coefficient? If you don't want advection due to the flow velocity, it seems like you should use a diffusive transport equation and adjust the diffusion coefficient to get the desired behavior. I know that in turbulent particle-laden flow modelling they talk about particle "diffusion" even though particles don't really diffuse, but their response to the turbulent velocity fluctuations can be treated as a "diffusion". Tristan