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April 6, 2013, 03:05 
Wrong figure in Hrv. thesis?

#1 
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Santiago Marquez Damian
Join Date: Aug 2009
Location: Santa Fe, Santa Fe, Argentina
Posts: 430
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Hi there, a few days ago Dr. Axel Larreteguy told me about some concerns about Figure 3.7 in Hrv. thesis (see attachment). Here we have the vectors and , which have units of area and then vector , the correction, which seems to take in account the displacement of from the face centroid , so that it has units of distance. The concerns are:
1. Why the differences in units? 2. Do the vector decomposition make sense as is drawn? Below the figure it is stated that vector is not used 3. The correction vector is not used because simplification or because it is zero (I guess so)? Following the work of Mathur and Murthy http://www.tandfonline.com/doi/abs/1...915105#preview it leads to a zero correction. If it is the wrong interpretation 4. How do we interpret the figure? Thanks in advance,
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Santiago MÁRQUEZ DAMIÁN, Ph.D. Research Scientist Research Center for Computational Methods (CIMEC)  CONICET/UNL Tel: 543424511594 Int. 7032 Colectora Ruta Nac. 168 / Paraje El Pozo (3000) Santa Fe  Argentina. http://www.cimec.org.ar 

April 6, 2013, 14:53 

#2  
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Philip Cardiff
Join Date: Mar 2009
Location: Dublin,Ireland
Posts: 620
Rep Power: 21 
Quote:
Not sure if I can answer your questions, but In Hrv's thesis (and in OpenFOAM), nonorthogonal correction is not employed on the boundary. This assumption is fine if we assume that phi does not vary along the boundary. Although, if we assume that phi varies linearly along the boundary then nonorthgonal correction is required to maintain accuracy, as outlined in E. De Villiers thesis (Fig. 4.7). I believe that this correction is not performed in OpenFOAM because it may lead to mass flux across walls. But boundary nonorthogonal correction can be employed through use of custom boundary conditions, such as fixedDisplacement (corrected version of fixedValue) in the solidMechanics branch of OpenFOAM1.6ext. Hope it helped, Philip 

April 7, 2013, 01:37 

#3 
Senior Member
Santiago Marquez Damian
Join Date: Aug 2009
Location: Santa Fe, Santa Fe, Argentina
Posts: 430
Rep Power: 16 
Thanks Philip, it helped! I'm going to elaborate some ideas to post.
Regards.
__________________
Santiago MÁRQUEZ DAMIÁN, Ph.D. Research Scientist Research Center for Computational Methods (CIMEC)  CONICET/UNL Tel: 543424511594 Int. 7032 Colectora Ruta Nac. 168 / Paraje El Pozo (3000) Santa Fe  Argentina. http://www.cimec.org.ar 

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