We perform a combined analytical-numerical study of hydrodynamic sensitivity of a concentrated vortex in collision with a roughness wall. Models of the hydrodynamic instability and wall-bounded flow sensitivity are provided analytically by means of parabolization of the Navier-Stokes equations. The differential quadrature method was originally applied as a numerical technique to solve sets of linear algebraic equations by use of a uniform grid. We extend this technique to multidimensional clustered grids and we develop a two-level differential quadrature algorithm to compute the fluctuating flow and the sensitivity field. Extensive numerical results are presented for a two-dimensional Lamb–Oseen problem and both the solution accuracy and convergence rate are assessed. A variational flow control method is also investigated, that proved to be useful for mitigating the flow instabilities by setting the base flow to optimal parameters.