<p><a href="https://scicomp.stackexchange.com/">Computation Science</a>?   There's certainly some overlap of subject matter with CrossValidated. It's still in beta, and <a href="http://area51.stackexchange.com/proposals/28815/computational-science">needs more questions if it's ever to get past beta</a>. I'm not clear if migration to/from beta sites is allowed.</p>
