We propose a self-consistent, transient numerical study of negative corona discharges produced in front of a blunted body in a supersonic Mach 3 flow. Taking into account the supersonic flow field and the bow shock wave formation which includes variable gas temperature, density and velocity distribution, the plasma discharge dynamics is analyzed, revealing high frequency discharge pulses similar to typical Trichel pulses in point-to-plane, known to exist in atmospheric discharges without or with low-speed external flow, although the process giving birth to these pulses is completely different. Through numerical simulations we show how, after a first strong ionization phase happened in front of the blunt body, the supersonic flow field acts on the ionic species displacements and changes the local charge distribution so that a new ionization phase can take place. In order to assess more precisely this effect, a panel of numerical test-cases are proposed with different transport velocities of the charged species by the supersonic flow.