laminar model used for turbulent flow

raunakjung · December 3, 2016, 03:28

How are the Navier stokes equations solved in Navier Stokes equtions solved when laminar model is used ?
What happens when turbulent conditions are solved using Laminar model ?

Thank You

Antanas · December 3, 2016, 04:32

Quote:

Originally Posted by raunakjung

How are the Navier stokes equations solved in Navier Stokes equtions solved when laminar model is used ?
What happens when turbulent conditions are solved using Laminar model ?

Thank You

Laminar model means that full non-averaged N-S equations (not RANS) are solved. It will resolve all turbulent scales except subgrid scales. Generally it's not easy and costly. So its better to use laminar model when flow is really laminar.

FMDenaro · December 3, 2016, 15:51

The original NS equations are valid independently from the regime of the flow. Laminar, transitional and turbulent flows can be simulated provided you have a so fine grid to resolve all characteristic scales (DNS).

raunakjung · December 3, 2016, 19:08

I tried using LES in a laminar condition and the results are similar to when using a laminar model . What does this result means ?

FMDenaro · December 4, 2016, 03:42

Quote:

Originally Posted by raunakjung

I tried using LES in a laminar condition and the results are similar to when using a laminar model . What does this result means ?

Nothing particular, the LES code is well written

flotus1 · December 4, 2016, 04:08

You should really stop using the term laminar "model". The point of a direct numerical simulation (DNS, what you refer to as laminar "model") is that there are no additional models necessary. The Navier-Stokes equations are solved directly.

December 3, 2016, 03:28	laminar model used for turbulent flow	#1
raunakjung Senior Member raunak jung pandey Join Date: Jun 2016 Posts: 102 Rep Power: 8	How are the Navier stokes equations solved in Navier Stokes equtions solved when laminar model is used ? What happens when turbulent conditions are solved using Laminar model ? Thank You

December 3, 2016, 15:51		#3
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,388 Rep Power: 67	The original NS equations are valid independently from the regime of the flow. Laminar, transitional and turbulent flows can be simulated provided you have a so fine grid to resolve all characteristic scales (DNS). lcarasik likes this. Last edited by FMDenaro; December 4, 2016 at 03:42.

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December 3, 2016, 19:08		#4
raunakjung Senior Member raunak jung pandey Join Date: Jun 2016 Posts: 102 Rep Power: 8	I tried using LES in a laminar condition and the results are similar to when using a laminar model . What does this result means ?

December 4, 2016, 04:08		#6
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,307 Rep Power: 44	You should really stop using the term laminar "model". The point of a direct numerical simulation (DNS, what you refer to as laminar "model") is that there are no additional models necessary. The Navier-Stokes equations are solved directly.