HdivB/B rapidly increasing in colliding flows

danieljprice / phantom

Phantom Smoothed Particle Hydrodynamics and Magnetohydrodynamics code

https://phantomsph.github.io

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HdivB/B rapidly increasing in colliding flows #519

Closed teogeo1996 closed 4 months ago

teogeo1996 commented 6 months ago

Whilst running simulations including the creation of a shock compressed layer, the value of HdivB/B rockets well above one even after setting hdivbbmax_max=512 as recommended by the code. Changing overcleanfac to account for this essentially makes the code extremely slow. Is there another way to go about this issue?

danieljprice commented 6 months ago

not really, at some point you have to pay the cost to get div B lower... the only other thing here is that we use a cleaning speed of sqrt(cs2 + va2) so if you're highly super-Alfvenic then a higher cleaning speed (overcleanfac) could help without killing the timestep too much...

danieljprice commented 4 months ago

we recently pushed a fix that may fix the problem here, see #537