Giuseppe Bilotta<p>This, BTW, is why we developed a semi-implicit formulation that handles the viscous part (only) implicitly:<br><a href="https://www.sciencedirect.com/science/article/abs/pii/S002199911830593X" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://www.</span><span class="ellipsis">sciencedirect.com/science/arti</span><span class="invisible">cle/abs/pii/S002199911830593X</span></a><br><a href="https://www.sciencedirect.com/science/article/abs/pii/S0021999122004752" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://www.</span><span class="ellipsis">sciencedirect.com/science/arti</span><span class="invisible">cle/abs/pii/S0021999122004752</span></a><br>(the latter may be of interest to you if you use <a href="https://fediscience.org/tags/BiCGSTAB" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>BiCGSTAB</span></a> or <a href="https://fediscience.org/tags/ConjugateGradient" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>ConjugateGradient</span></a> methods to solve linear systems that have nothing to do with SPH, BTW).</p><p>And now comes the new difficulty: THERMAL!</p><p>6/n</p>