<div dir="ltr"><div class="gmail_default" style="font-size:small">Hello All,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">I want to run MHD case with different magnetic diffusivities in different region of the domain.</div><div class="gmail_default" style="font-size:small">Can we run MHD run with different magnetic diffusivities?</div><div class="gmail_default" style="font-size:small">Assuming that udiff=magnetic diffusivity (eta), in the uservp file I added the following<br></div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small"><div class="gmail_default">      1.0000000E+00     p30 > 0 ==> properties set in uservp()</div><div><br></div></div><div class="gmail_default"><div class="gmail_default"><div class="gmail_default">      subroutine uservp (ix,iy,iz,ieg)</div><div class="gmail_default">      include 'SIZE'</div><div class="gmail_default">      include 'TOTAL'</div><div class="gmail_default">      include 'NEKUSE'</div><div class="gmail_default"><br></div><div class="gmail_default">      if (ifield.eq.1) then<span class="gmail-Apple-tab-span" style="white-space:pre">               </span>! velocity</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">             </span>utrans = param(1)</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">              </span>udiff  = param(2)</div><div class="gmail_default">      elseif (ifield.eq.ifldmhd) then<span class="gmail-Apple-tab-span" style="white-space:pre">     </span>! B-field</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">              </span>utrans = 1.0</div><div class="gmail_default">        R1 = sqrt(x*x+y*y); </div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">           </span>if(R1 .le. 2.0) then</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">                   </span>udiff= param(29)</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">               </span>else</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">                   </span>udiff= 1000.0D0*param(29)</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">              </span>endif</div><div class="gmail_default"><span class="gmail-Apple-tab-span" style="white-space:pre">  </span>  endif<span class="gmail-Apple-tab-span" style="white-space:pre">      </span></div><div class="gmail_default">      </div><div class="gmail_default">      return</div><div class="gmail_default">      end</div><div class="gmail_default"><br></div><div class="gmail_default">I get an error </div><div class="gmail_default"><br></div><div class="gmail_default"><div class="gmail_default"> done :: set initial conditions</div><div class="gmail_default">  </div><div class="gmail_default">  ERROR:  Non-positive diffusivity (    0.00    ) specified for field 2, group 0 element</div><div class="gmail_default">  ERROR:  Non-positive diffusivity (    0.00    ) specified for field 2, group 0 element</div><div><br></div><div>Attached are the .usr, .rea and the logfile</div><div><br></div><div>When I set the p30=0.000 and just utrans=0.0 udiff=0.0 in the uservp, the simulation is running fine.</div><div>Thank you in advance.</div><div><br></div><div>Cheers,</div><div>Sandeep</div></div><div class="gmail_default"><br></div><div><br></div></div></div></div>