Numerical Simulations on the Effect and Efficiency of Long Linear Energy Deposition Ahead of a Supersonic Blunt Body: Toward a Laser Spike

The effect of single or repetitive linear energy depositions in front of a supersonic blunt body is computed using the CEDRE flow solver. The CFD Code models the effect of a laser-induced energy deposition, as obtained for example using the long filaments created by a femtosecond laser. Single energy depositions show that significant transient drag reductions are obtained, due to the interaction of the heated core, created by the energy release, with the bow shock. When the deposition is repeated, cumulative effects are important and quasi-steady or unsteady flow regimes are obtained, depending on the power and repetition frequency. This behavior is similar to that obtained with supersonic spiked blunt bodies, acting like a laser spike. This system can lead to 15%-20% fuel savings, depending on the energy deposition efficiency.