<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Sean and all,<div class=""><br class=""><div class=""><div><div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; font-size: 14px;" class=""></div><blockquote type="cite" class=""><div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; font-size: 14px;" class="">I’ve also encountered this same issue at refinement jumps with USM. I could never get HLLD to behave. What I found was ok was to use HLLC with high-order electric field construction. Then, even better, I turned on magnetic resistivity with a small value. That smoothed things out nicely. <br class=""></div></blockquote><div><br class=""></div><div>I suspect that this is not the best solution for all problems, especially if you’re trying to model some other non-ideal effect such as viscosity or resistivity. It probably depends on what you’re trying to do. </div><br class=""><blockquote type="cite" class=""><div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; font-size: 14px;" class="">May “belief” at this point is that either: 1) staggered mesh CT simply does not behave well with AMR, or 2) the prolongation/restriction routines in PARAMESH for face variables is bugged somehow. </div><div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; font-size: 14px;" class=""><br class=""></div><div style="font-family: -apple-system, BlinkMacSystemFont, sans-serif; font-size: 14px;" class=""><span style="caret-color: rgb(213, 218, 222);" class="">John Z., Is this for the mesh refinement versions of Athena and Athena++? Or uniform grids? </span><br class=""></div></blockquote><div class=""><span style="caret-color: rgb(213, 218, 222);" class=""><br class=""></span></div><div class=""><span style="caret-color: rgb(213, 218, 222);" class="">Mesh refinement version of both Athena and Athena++, since I have used both for the same problem as FLASH and not seen the issue. I have not used the GAMER code for this purpose (I will soon) but I have heard from the main developer Justin Schive that he hasn’t seen it either. For these reasons, I do suspect the issue is in PARAMESH or elsewhere in FLASH</span><span style="caret-color: rgb(213, 218, 222);" class=""> somewhere. </span></div><div class=""><span style="caret-color: rgb(213, 218, 222);" class=""><br class=""></span></div><div class=""><span style="caret-color: rgb(213, 218, 222);" class="">John</span></div></div></div></div></body></html>