<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi all,<div><br></div><div>Recently, I noticed that yt lacked a feature I needed to analyze a protostellar disk simulation. For this work, I'd like to be able to plot the average azimuthal and radial velocity as a function of radius. Since my disk is not aligned with the grid, it's a bit of a pain to do this while referring only to the grid-aligned coordinates.</div><div><br></div><div>To fix that situation, I took it upon myself to add new fields that project the velocity and magnetic field onto a cylindrical or spherical coordinate system with an arbitrary orientation.</div><div><br></div><div>If you're on the development branch of yt, the next time you run 'yt update', you'll have several new derived fields available:</div><div><br></div><div>cyl_TangentialVelocity,</div><div>cyl_RadialVelocity,</div><div>BPoloidal,</div><div>BPoroidal,</div><div>BPadial</div><div><br></div><div>These fields supplement the already available TangentialVelocity and RadialVelocity, which refer to a spherical coordinate system.</div><div><br></div><div>The new fields allow me to write a script like this: <a href="http://paste.yt-project.org/show/2786/">http://paste.yt-project.org/show/2786/</a></div><div><br></div><div>To make this work, I've written a framework for converting coordinates and vector fields from cartesian to cylindrical and spherical coordinates. If you have some other vector field that you'd like to look at in a different coordinate system, this framework should be exactly what you need!</div><div><br></div><div>If you'd like more details, let me know and I'll do my best to help.</div><div><br></div><div>Cheers,</div><div><br></div><div>Nathan Goldbaum</div></body></html>