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

Drag coefficient for a sphere

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   July 5, 2011, 12:21
Default Drag coefficient for a sphere
  #1
New Member
 
Join Date: Apr 2011
Location: Magdeburg, Germany
Posts: 23
Rep Power: 6
Nico A. is on a distinguished road
Hello to all,

I am doing simulations on a sphere at high Re ( 1*e5 - 1*e7 ) using the k-omega-SST turbulence model. Unfortunatly I got the same drag coefficient (Cd) for the different Re and also flow behavior looks the same.
Code:
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     simpleFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         1200;

deltaT          1;

writeControl    timeStep;

writeInterval   50;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression uncompressed;

timeFormat      general;

timePrecision   6;

runTimeModifiable yes;

functions
{
	forces
	{
		type forces;
		functionObjectLibs ( "libforces.so" ); 		
		outputControl timeStep;
		outputInterval 1;
		patches
		(
		sphere					
		);
								
		rhoName rhoInf;
		log true;					
		rhoInf 1.2041;
		CofR ( 0 0 0 );
	}
	forcesCoeffs
	{
		type forceCoeffs;
		functionObjectLibs ( "libforces.so" ); 		
		outputControl timeStep;
		outputInterval 1;
		patches
		(
		sphere 					
		);
								
		rhoName rhoInf;
		log true; 					
		rhoInf 1.2041;
		CofR ( 0 0 0 );
		liftDir ( 0 1 0 );
		dragDir ( 1 0 0 );
		pitchAxis ( 0 0 0 );
		magUInf 15;
		lRef 0.4;
		Aref 0.125662;
	}
}
I allways adjusted the values for k and omega the different velocities at the inlet (and also at the sphere/wall). I am not sure which values can be changed and which must not be changed. Does anyone have some advices?

Best regards Nico
Nico A. is offline   Reply With Quote

Reply

Thread Tools
Display Modes

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Drag Coefficient Convergence Problem John FLUENT 16 September 4, 2009 02:44
Drag coefficient for parcels in dieselFoam sebastian_vogl OpenFOAM Running, Solving & CFD 5 December 31, 2008 13:19
Automotive test case vinz OpenFOAM Running, Solving & CFD 98 October 27, 2008 09:43
CFX analysis of a sphere - drag too low Rob Findlay CFX 6 March 26, 2007 10:11
meshing F1 front wing Steve FLUENT 0 April 17, 2003 12:37


All times are GMT -4. The time now is 15:43.