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

Calculation of the deformation rate

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 19, 2009, 13:50
Unhappy Calculation of the deformation rate
  #1
Senior Member
 
Antonio Martins
Join Date: Mar 2009
Location: Porto, Porto, Portugal
Posts: 112
Rep Power: 8
titio is on a distinguished road
Send a message via MSN to titio Send a message via Skype™ to titio
Hi Foamers,

i am currently trying to model non-newtonian flow using OpenFoam and based on the PISO as implemented in the icoFoam solver, and I stumbled in the calculation of the deformation rate. At least so I think because the results I am getting for a comparison case with an a analytical solution.

I am calculating thye deformation rate using the following formula

DR=DU+DUT

where DU=fvc::grad(U) and DUT=DU.T(). DU, DUT and DR are defined as tensor fields, that were all initialized in the createFields.h file, although they are not defined in the vector and tensorial fields defined in the 0 folder. The code I added to the file is the following

volTensorField DU
(
IOobject
(
"DU",
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::NO_WRITE
),
fvc::grad(U)
);

volTensorField DUT
(
IOobject
(
"DUT",
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::NO_WRITE
),
DU.T()
);

volTensorField DR
(
IOobject
(
"DR",
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::NO_WRITE
),
DU + DUT
);

DU, DUT and DR are all recalculated in all iterations of PISO algorithm. Thus, all formulas are repeated in the main code of the solver I developed.

Is the code that I presented O.K? When I compared predicted with analytical results, it looks like I not getting the values of the deformation rate I should have.

Anyone have some idea how to properly represent the tensor fields, and to calculate the deformation rate I woulf greatly appreciate.

Titio
titio is offline   Reply With Quote

Old   March 22, 2009, 09:45
Default
  #2
New Member
 
Kerstin Heinen
Join Date: Mar 2009
Location: Ludwigshafen, Germany
Posts: 27
Rep Power: 8
kerstin is on a distinguished road
Check this thread
StrainRate definition 141 vs 15
The search function of the forum is your friend ;-)

Last edited by kerstin; March 22, 2009 at 09:48. Reason: wrong link
kerstin 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
heat release rate calculation Karthick .K FLUENT 1 February 27, 2014 20:55
shear rate calculation Stephane bone CD-adapco 2 January 7, 2005 12:34
Taylor deformation rate Junseok Kim Main CFD Forum 0 July 16, 2004 13:16
Mass Flow Rate Calculation Paul FLUENT 9 March 23, 2002 09:37
difference rate of deformation and strain...?! Bob FLUENT 0 March 1, 2002 13:47


All times are GMT -4. The time now is 01:03.