Effects of static aeroelastic deformation of a wind-tunnel test model on the aerodynamic characteristics are discussed in supersonic wind-tunnel tests. The static aeroelastic deformation of the main wing of a supersonic airplane model in the JAXA 1m×1m supersonic wind-tunnel is estimated by the iteration of the full-potential aerodynamic analysis and the FEM structural analysis. The estimated deformation corrections improve the agreement of the measured and predicted aerodynamic performance of the model. Some simple aerodynamic load estimation models are constructed with a few aerodynamic calculation results in order to improve the efficiency of the static aeroelastic deformation estimation for practical applications.
The mathematical optimization of the nozzle configuration of self-field magneto-plasma-dynamic thrusters (MPDT) is quite difficult because of the calculation cost. In this paper, we proposed an optimization method based on a response surface method and optimized the shape of the discharge chamber of a self-field MPDT, using a 2-dimensional axially symmetric model of plasma flow. We searched the optimum shape with maximum thrust efficiency under the condition of 8,000A of discharge current, and discussed optimum shape changes when input power was changed. As a result, we could get the optimum shape with only about 100 CFD calculations, and found out that the optimum configuration had a flared anode and a long cathode in about 200 to 400kW region.
The characteristic velocity C* is derived from the assumption of one-dimensional flow in a uniform pressure field, and is usually evaluated using a combustion chamber pressure measured on the chamber wall. In the swirling-oxidizer-flow-type hybrid rocket engines, the C* efficiency in excess of 1.0 was sometimes measured due to an increased wall pressure in the centrifugal force field of the swirling flow. It was induced that the specific impulse efficiency was useful to evaluate the C* efficiency accurately without using the combustion chamber pressure when the CF efficiency was given. This evaluation method of the C* efficiency was confirmed to be appropriate and available by the burning tests using the swirling-oxidizer-flow-type hybrid rocket engines with optimum expanding nozzles.
This paper describes development of noise reduction devices for aircraft landing gear. The design process of noise reduction devices is based on unsteady CFD analysis. Unsteady CFD analysis is done by in-house CFD code, which utilize unstructured Cartesian grid system and higher order accuracy numerical scheme. Maintenance acceptance was taken into account in selection of devices. The developed devices were tested in low noise wind tunnel. The test results successfully showed 3dBA (over all) noise reduction.