Advection for steep slopes and arbitrary meshes

2017-02-14T19:50:11Z (GMT) by James Shaw
<div><div>Almost all operational weather forecast models represent terrain using terrain-following meshes that become highly-distorted over steep slopes.  An alternative is the cut cell method but, while cut cell meshes are less distorted compared to terrain-following meshes, arbitrarily small cut cells are created that constrain the time-step for explicit numerical methods.</div></div><div><br></div><div><div>This motivates a new type of mesh that avoids arbitrarily small cells and most mesh distortions.  Combined with a new multidimensional method-of-lines advection scheme that is formulated for stability and accuracy over steep slopes on arbitrarily-structured meshes, we alleviate numerical instabilities and inaccuracies associated with traditional advection schemes.</div></div><div><br></div><div><div>Presented at the workshop on numerical methods for geophysical fluid dynamics</div><div>at Imperial College London, 14th February 2017.</div></div>