# Boundary conditions for simpleSRFFoam

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

 September 14, 2008, 18:56 I am trying to set up a case t #1 Senior Member   Chris Sideroff Join Date: Mar 2009 Location: Ottawa, ON, CAN Posts: 371 Rep Power: 12 I am trying to set up a case to use simpleSRFFoam and in general have been able to follow the 'mixer' example, despite no documentation existing for this application. The question I have is setting boundary conditions. In the 'mixer' example, the inlet has the following: inlet { type SRFVelocity; inletValue uniform (0 0 -10); relative yes; value uniform (0 0 0); } From what I can see, to set an boundary condition in relative terms, the type must be set to 'SRFVelocity'. What is the purpose of setting both an 'inletValue' and 'value'? Is it documented anywhere how boundary conditions can be applied with type 'SRFVelocity'? Or does anyone having an experiences with setting boundary conditions for this application? Thanks, Chris

 September 24, 2008, 09:12 hi Chris here is the answer yo #2 New Member   Franz Join Date: Mar 2009 Posts: 17 Rep Power: 8 hi Chris here is the answer you can find that usually in the src/finiteVolume/fvPatchFields/derived (or search for SRFVelocity in the source code ) it is the definition of the boundary condition void SRFVelocityFvPatchVectorField::updateCoeffs() { if (updated()) { return; } // If relative, include the effect of the SRF if (relative_) { // Get reference to the SRF model const SRF::SRFModel& srf = db().lookupObject("SRFProperties"); // Determine patch velocity due to SRF const vectorField SRFVelocity = srf.velocity(patch().Cf()); operator==(-SRFVelocity + inletValue_); } // If absolute, simply supply the inlet value as a fixed value else { operator==(inletValue_); } fixedValueFvPatchVectorField::updateCoeffs(); } Best regards Franz

 September 24, 2008, 09:47 Oh and the value is the initia #3 New Member   Franz Join Date: Mar 2009 Posts: 17 Rep Power: 8 Oh and the value is the initial value of the Patch. Which means after one timestep if it is relative the value becomes equal to (-SRFVelocity + inletValue_); done with the operator== Franz

 February 6, 2009, 09:22 Hi. I'm having problems getti #4 Senior Member   David Boger Join Date: Mar 2009 Location: Penn State Applied Research Laboratory Posts: 146 Rep Power: 8 Hi. I'm having problems getting a simpleSRFFoam case going. It is basically a propeller case. "SRFProperties" includes following: SRFModel rpm; axis (-1 0 0); rpmCoeffs { rpm 6.2; } "boundary" includes this for the inlet: inlet { type patch; nFaces 1920 ; startFace 2222592 ; } and the 0/Urel file includes this for the inlet: inlet { type fixedValue; value nonuniform List 1920 ( (0.99658608351715038953 -0.92954434724578038907 0.18320505536387468593) ..and so on. ); } After 1000 steps, if I examine the solution in Fieldview (foamToFieldview9), the relative and absolute velocities both look to be specified correctly on the inlet (and other) boundaries. But the swirl that is imposed at the inlet is immediately "lost" after the first cell; the flow immediately becomes axial once it leaves the inflow boundary. The internalField velocity in Urel is set to uniform (1 0 0), but after 1000 steps, I'd expect this to be gone, so I suspect I'm setting the inflow or rotation incorrectly. I've read here but don't understand the SRFVelocity tag in the boundary specification. Is it needed here? Is there something else I could be missing? Thanks, David __________________ David A. Boger

June 17, 2010, 13:37
#5
New Member

Sunny William
Join Date: Jun 2010
Location: London
Posts: 6
Rep Power: 7
Hello,
I am also using simpleSRFFoam to simulate a turbomachinery case, however, I get the same problem as David.

Quote:
 Originally Posted by dab143psuedu swirl that is imposed at the inlet is immediately "lost" after the first cell; the flow immediately becomes axial once it leaves the inflow boundary.
Could you let me know if this problem has been solved?

Many thanks,
San

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post abchavz OpenFOAM Bugs 0 February 7, 2009 13:14 waynezw0618 OpenFOAM Running, Solving & CFD 2 December 7, 2008 04:45 miku OpenFOAM Running, Solving & CFD 4 November 4, 2008 11:51 arkangel OpenFOAM Running, Solving & CFD 1 October 2, 2008 14:48 olesen OpenFOAM Running, Solving & CFD 0 July 27, 2006 07:18

All times are GMT -4. The time now is 08:26.