Hi all: In solving N-S eqns. using finite elements, some elements are LBB (Ladyzanskya Babuska Brezzi) stable and others are not. For instance, linear triangular elements with non-staggered grids (solving for u,v,w,p at every grid point) are proven to be LBB non-compliant. Can some expert explain (in simple and clear terms), (i) What is this LBB condition (here I am damn scared of Mathematical proofs and I want a more physics based explanation) ? (ii) What will happen if we choose LBB non-compliant elements (results will be inaccurate or something extra ?)