Hi everyone, I'm trying to use the APE Solver in nektar++ to predict sound generation from a particular industrial flow. The work is similar in scope to that published in this recent paper : http://www.iccfd.org/iccfd10/papers/ICCFD10-248-Paper.pdf. I'm particularly interested in how to define the source term. If I understand the work correctly, in a flow dominated by coherent structures, the Lamb vector becomes the dominant source. This leads to my first question : 1.In the APE-4 formulation there are 2 coupled equations with seperate source terms - one for the pressure fluctuations and one for the velocity fluctuations. In the above paper when the authors state that only the lamb vector was considered as a source, was the source for the RHS of the pressure fluctuations set to zero? 2. If this was the case, how was this specified in the .xml file? The only example I have come across is in the user guide which shows <FUNCTION NAME="Source"> <E VAR="S" VALUE="0" /> </FUNCTION> If one wanted to specify the pressure and velocity source terms seperately how would one do it in the .xml file? 3. From older posts in the mailing list I have seen suggestions of a workflow where the .chk/.fld files are written into a .pts file and then post processed to obtain the acoustic source. Is there a relevant filter or an extension the FieldConvert module that allows direct conversion from a .fld/.chk to a .pts format? I know of the interppoints extension that allows export to a .dat format but not the .pts? Sorry for the lengthy post. Thanks in advance! -- *Amitvikram Dutta* Graduate Research Assistant Fluid Mechanics Research Lab Multi-Physics Interaction Lab University of Waterloo