Previous efforts in topology optimisation have been mostly dedicated to steady flows, and to significantly minor extent, to transient flows where time dependence followed an active function imposed to the inlet [1-5]. All these cases involved stable flows --- wherein the transience did not withstand in time, rather, it was only sustained as long as the external forcing was maintained through boundary conditions. However, self-excited unsteadiness is a matter that has not been treated in topology optimisation, even though a host of practical applications are subject to its effects. In particular, vortex shedding is detected and dominates fluid-structure interactions --- ranging from compressible flows in the interior of compressor rotors all the way up to incompressible ones past massive bluff hulls of oil platforms. This work is driven by the desire of harnessing these flows and suppressing wake dynamics. In order to do so, we employ topology optimisation, wherein fluid and solid are freely distributed in a design domain driven by a gradient-based algorithm to minimise energy dissipation and yet respect volume fraction constraints. The direct problem is solved through finite volume simulations in OpenFOAM. Our sensitivity analysis employs a novel strategy to ensure good agreement between finite differences and automatic differentiation through FEniCS/dolfin-adjoint alongside reasonable computational cost. Our optimised designs reduce energy dissipation, attenuate and suppress the wake, as well as the associated lift and drag, by employing upper and lower bounds on the volume fraction. Moreover, the resulting structures resemble classical passive-flow control designs, which were not optimised previously (such as oblique plates, fairings, splitter plates and control rods). Physical considerations are rigorously scrutinised and support our findings.