جریان ابرصوتی

In this research, procedure of aerodynamics design for hypersonic wind tunnel test section is investigated by using computational fluid dynamics. The type of test section is chosen closed-type free jet. First, conceptual design is done by using the available statistical data in the hypersonic wind tunnel test section in the world. Then, quality of design is investigated by numerical simulation by solving Navier-Stokes equations in compressible, viscous (k-w SST model) and axisymmetric form. With changing the parameters of the test section, the test section dimensions have been optimized. The important parameters in test section are length of the test section, the test section diameter, the diameter of the inlet diffuser, the diffuser and the nozzle indentation inside the test section. Design criteria are chosen the formation of uniform flow, better swallow the slip line and the flow deflection in the test section. Finally, dimensions, specifications and aerodynamics functional requirements of the hypersonic wind tunnel test section have been determined at Mach 5 to 7. The effect of cone and curved nozzles is also investigated for flow quality in test section of wind tunnel.

In this work, the problem of designing a hypersonic vehicle with high lift-drag ratio in hypersonic rarefied regimes is investigated. At high altitudes, the assumption of continuity employed in the Navier Stocks equations is no longer true and is not possible to simulate the problem with conventional CFD routines. The Direct Simulation of Monte Carlo (DSMC) which is a particle-based method was employed to simulate the hypersonic rarefied regimes of hypersonic vehicles. In the first step, based on momentum theory, a simple definition for increasing aerodynamic efficiency was provided. According to this definition, a two-dimensional body under considerations of hypersonic-rarefied flow regimes was analyzed using the DSMC code of DS2V. According to the facts obtained from this analysis, we considered a typical three-dimensional body, and developed the configurations of high aerodynamic efficiencies. The simulations were conducted in three-dimensional space by the DSMC program of DS3V showed that the abovementioned definition is applicable to three-dimensional geometries. Finally, based on authenticated definitions, we exemplified a three-dimensional body, which is capable to produce high aerodynamic efficiencies in hypersonic regimes at high altitudes.

The purpose of this investigation is consideration of aerothermodynamic phenomena over blunt and slender pointed bodies in hypersonic flows. Such results may be obtained by numerically solving the full Navier-Stokes equations or one of their various subsets، such as PNS equations. However، due to the excessive computer storage and CPU requirements، most people use their simple forms. In this work، a computer code was developed that uses an implicit finite difference method to solve non-similar، full compressible boundary layer equations for laminar، transitional، and turbulent flows over blunt and slender pointed bodies in hypersonic flows. Different test cases were studied and the related results were compared to benchmark CFD and experimental data showing relatively close agreements.