Bifurcations and inviscid limit of rhombic Navier-Stokes flows in tori

We consider viscous incompressible fluid motions on two-dimensionaltori. Unlike many papers which treat the cases where the basicflow is a parallel flow, we consider here the case where theflow pattern is rhombic. We numerically compute the bifurcatingsolutions and find that (1) the bifurcating branch is a transcriticalone, (2) on one side of the branch, the solution displays asharp interior layer in the inviscid limit, and (3) on the otherside of the branch, the solutions in the inviscid limit do notpossess an interior layer.