CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Drag coefficient implementation

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 24, 2020, 12:02
Default Drag coefficient implementation
  #1
New Member
 
Sumit Peh
Join Date: Oct 2018
Location: Beijing
Posts: 20
Rep Power: 8
Jamessmp23 is on a distinguished road
Hi Foamers

I would like to apply equations of other Drag coefficient in 4 conditions of Renold's number.
[Re<1 // 1<Re<100 // 100<Re<1000 // Re>1000]

SchillerNaumann has 2 conditions of Re which are Re<1000 and Re>1000
Here is the SchillerNaumann code on ~dragModels
I supposed neg(Re - 1000) is this Re<1000 condition and pos0(Re - 1000) is the Re>1000.

Code:
{
    volScalarField Re(max(Ur*phase1_.d()/phase2_.nu(), scalar(1.0e-3)));
    volScalarField Cds
    (
        neg(Re - 1000)*(24.0*(1.0 + 0.15*pow(Re, 0.687))/Re)
      + pos0(Re - 1000)*0.44
    );

    return 0.75*Cds*phase2_.rho()*Ur/phase1_.d();
}
Is there a way to write code for more than 2 conditions ?

As my imagination, I guess maybe my case would be
Code:
{
    volScalarField Re(max(Ur*phase1_.d()/phase2_.nu(), scalar(1.0e-3)));
    volScalarField Cds
    (
        neg(Re - 1)*(Equation1)
      + neg1(Re - 100)*(Equation2)
      + neg100(Re - 1000)*(Equation3)
      + pos0(Re - 1000)*(Equation4)
    );

    return 0.75*Cds*phase2_.rho()*Ur/phase1_.d();
}
Please confirm if i'm right and please correct if i'm wrong.

Thanks in advanced

James
Jamessmp23 is offline   Reply With Quote

Reply

Tags
cfd, drag, drag coefficient, openfoam


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Drag Force Ratio for Flat Plate Rob Wilk Main CFD Forum 40 May 10, 2020 05:47
problem with saving drag coefficient colopolo FLUENT 5 April 12, 2013 11:59
Calculation of Drag Coefficient, Help Please teek22 CFX 1 April 26, 2012 19:41


All times are GMT -4. The time now is 14:03.