Dear Sirs,

My research institution assigned me a task to investigate the problem of numerical modeling of a 3D flow of incompressible viscous fluid circumventing a dimpled surface. The regime of the flow can be both laminar and turbulent. Now I must make a decision what to do and I have at least two options:

A. To realize this numerical algorithm using the resources of our institution (this means to write this software packet myself or with the help of a group of programmers).

B. To get this software packet from some third party.

I would be very much obliged to you if you could give me some advice. In case I choose option B. is it possible to get a quality product without spending big sums of money? If it is not possible and I should choose option A. what numerical method could you recommend (e.g. SIMPLE, QUICK, TVD, 3DFCT etc.)? As I know there are plenty of some shareware and freeware products available but I have some doubt about their reliability.

I would be very much obliged for any help or advice. Thank you in advance.

Respectfully yours, Yuri Solodoukhov

as for option A. there is a wide variety of commercial codes out there for viscous in compressible flow. if you work at a university they often have special academic licenses which cost much less than the usual commercial licenses. it would be a good idea for you to get in contact with the vendors of these codes by way of their websites. CFD online also has other discussion groups focused on commercial products so you can inquire there about more details. as you alluded to before there are also free/share ware codes available. i don't think that you should ignore these out of hand. you should check aroundand ask questions of the developers to see what these codes can do. often the codes have been used in research papers that you can read to help gauge the effectiveness of these codes. ready made codes are also available from various government laboratories like NASA and the various dept of defense and energy labs in the US, INRIA in france and DLR in germany these codes may often have access restricted by nationality but they are worth checking out if only to see what schemes are currently being used. also many researchers at various universities have developed codes for research that you may want to check out. most of these research codes are available as source code which allows you to modify and understand the implementation better. even if you decide not to use a ready made code having a source code in front of you can help you write your own. B. your best resource for finding out about state of the art in compressible CFD would be various journals and technical papers, also there are books (mostly paper collections) which give an overview of the latest in the field. there may be journals dedicated to compressible flow (it's not really my specialty) i know that the von karman institute published a cfd lecture series book that mostly concentrated on incompressible flow you may want to contact them at http://www.vki.ac.be also you may want to read the CFD online resources section. most commercial codes today use pressure based methods like SIMPLE(R and C) or PISO for incompressible and compressible flow. but a lot of research has been done using the time iterative techniques developed for compressible flows using preconditioning for acceleration and dual time stepping where time accuracy is required. the VKI 30th lecture series on CFD is focussed on this. see http://www.vki.ac.be/educat/lect-ser/index.html hope this helps