# Convective terms schemes

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 June 14, 2018, 07:21 Convective terms schemes #1 New Member   Khaled Ahmad Join Date: Dec 2015 Posts: 26 Rep Power: 5 What is the most common differencing scheme used for convective terms recently? The cases are sudden expansion and a flow over cylinder. The flow is incompressible. Using FV method and RANS The grid is non-orthogonal non-staggered structured

June 14, 2018, 07:56
#2
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Filippo Maria Denaro
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Quote:
 Originally Posted by kh.aa What is the most common differencing scheme used for convective terms recently? The cases are sudden expansion and a flow over cylinder. The grid is non-orthogonal non-staggered structured

Considering only incompressible flows, I can suggest using FV formulation to fulfill conservation of mass and momentum. Often the type and order of the discretization depends on what formulation you use (RANS/LES/DNS).

June 14, 2018, 08:07
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 Originally Posted by FMDenaro Considering only incompressible flows, I can suggest using FV formulation to fulfill conservation of mass and momentum. Often the type and order of the discretization depends on what formulation you use (RANS/LES/DNS). You should provide more details about your interest

I am using FV with RANS formulation and the flow is incompressible.

June 14, 2018, 08:09
#4
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Filippo Maria Denaro
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Quote:
 Originally Posted by kh.aa Thanks for your reply and sorry, I was not clear. I am using FV with RANS formulation and the flow is incompressible.

In this case you do not need high accuracy order provided by recent advanced discretizations and also upwind schemes can be used.

 June 14, 2018, 08:17 #5 New Member   Khaled Ahmad Join Date: Dec 2015 Posts: 26 Rep Power: 5 I see. I was intending to use the Upwind scheme. I was afraid that this will affect the accuracy. But can you please state the reasons that no need to use higher order schemes for such conditions? Thanks

June 14, 2018, 08:22
#6
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Filippo Maria Denaro
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Quote:
 Originally Posted by kh.aa I see. I was intending to use the Upwind scheme. I was afraid that this will affect the accuracy. But can you please state the reasons that no need to use higher order schemes for such conditions? Thanks

The contribution given by the RANS model has greater magnitude order than the local truncation error of the discretization. You will not get advantage in using high order schemes