Pontryagin's principle is used to study the shape of the supersonic part of the nozzle of a carbon dioxide gas-dynamic laser whose gain is maximal. The exact shape is obtained for the uncoupled approximation of Anderson's bimodal model. In this case, if sharp corners are allowed, the ceiling of the supersonic part consists of a slant rectangular sheet followed by a horizontal one; otherwise...

In this paper, we continue to study the mechanisms of the receptivity of the supersonic boundary layer to free-stream disturbances by using both direct numerical simulation and linear stability theory. Specifically, the receptivity of a Mach 4.5 flow over a flat plate to free-stream fast acoustic waves is studied. The receptivity to free-stream slow acoustic waves, entropy waves and vorticity w...

1. Summary Alternative configurations for more efficient supersonic aircraft are suggested by consideration of the sources of drag at high speeds. Results of studies described in this paper indicate that supersonic aircraft with much higher efficiencies than previously achieved are possible with reduced Mach number. The paper focuses on two promising candidate solutions: oblique wings and confi...

Direct numerical simulation is used to investigate the transition induced by threedimensional isolated roughness elements in a supersonic boundary layer at a free stream Mach number of 3.5. Simulations are performed for two different configurations: one is a square planform roughness and the other is a diamond planform roughness. The mean-flow calculations show that the roughness induces counte...

The aim of this work is to analyze a viscous flow around the axisymmetric blunt body taken into account the mesh size both in the free stream and into the boundary layer. The resolution of the Navier-Stokes equations is realized by using the finite volume method to determine the flow parameters and detached shock position. The numerical technique uses the Flux Vector Splitting method of Van Lee...

The equations of RFD can be written as a hyperbolic system of conservation laws by choosing an appropriate vector of unknowns. We give an explicit formulation of the full spectral decomposition of the Jacobian matrices associated to the uxes in each spatial direction, which is the essential ingredient of the techniques we propose in this paper. These techniques are based on the recently derived...

The hollow-anode discharge is a special form of glow discharge. It is shown that a drastically reduced anode area is responsible for a positive anode voltage drop of 30-40 V and an increased anode sheath thickness. This leads to an ignition of a relatively dense plasma in front of the anode hole. Langmuir probe measurements inside a specially designed hollow anode plasma source give an electron...

The problem of the efficiency of particle acceleration for paraboloidal poloidal magnetic field is considered within the approach of steady axisymmetric MHD flow. For the large Michel magnetization parameter σ it is possible to linearize the stream equation near the force-free solution and to solve the problem self-consistently as was done by Beskin, Kuznetsova & Rafikov (1998) for monopole mag...

This paper discusses the design optimization of a wing for supersonic transport (SST) using a multiple-objective genetic algorithm (MOGA). Three objective functions are used to minimize the drag for supersonic cruise, the drag for transonic cruise, and the bending moment at the wing root for supersonic cruise. The wing shape is defined by 66 design variables. A Euler flow code is used to evalua...

As a first step towards the asymptotic description of coherent structures in compressible shear flows, we present nonlinear equilibrium solutions Navier--Stokes equations suction boundary layer (ASBL). The free-stream Mach number is assumed to be $< 0.8$ so that flow subsonic regime and assume perfect gas. We extend large-Reynolds structure theory \cite{deguchi_hall_2014a} for incompressible AS...