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形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2019-11-27, 資料番号: PA2010001000

A wind-tunnel test of an 80%-scale copy of the NASA Common Research Model was performed by the Japan Aerospace Exploration Agency using its 2 m×2 m transonic wind tunnel. The wind-tunnel model was fabricated by the Japan Aerospace Exploration Agency in consultation with NASA Langley Research Center and AIAA Drag Prediction Workshop committee members. The static aerodynamic forces and surface pressure distributions on the wing of the Japan Aerospace Exploration Agency model were measured at a relatively low Reynolds number of 2.27×106 due to tunnel capability limitations, where boundary-layer transition was simulated using optimized roughness. Measured data were compared with those of wind-tunnel tests of the Common Research Model obtained from NASA Langley Research Center’s National Transonic Facility as well as computational fluid dynamics predictions, both at a Reynolds number of 5.0×106. The comparison among these datasets required data normalization to the designed shape aligned at a reference condi...

In this study, unsteady pressure field caused by transonic buffeting phenomena on a generic transport model was analyzed using unsteady PSP. The tests were conducted in the JAXA 2-m Transonic Wind Tunnel at M=0.85 and the model angle of attack was varied between 2.5 and 6.8 degrees. From the obtained unsteady PSP data, the RMS of pressure fluctuation was calculated to detect the areas with strong shock oscillation. Spectral analysis was also conducted in order to find frequencies of shock oscillation and their correlation with pressure fluctuation. As the angle of attack increases, the shock position moves upstream and shock oscillation becomes stronger. At 6.8 degrees, two distinct areas with strong shock oscillation were observed. The spectral analysis shows that, under buffeting conditions, shock oscillation frequencies are distributed around either of 490 Hz or 365 Hz. Noticeable effects from the PSP coating on the measured aerodynamic forces were noticed, indicating that even the small roughness of the unsteady PSP coating has an influence on the transonic buffeting phenomena.

Dynamic stability tests of a reentry lifting capsule were conducted in the JAXA 2 m × 2 m Transonic Wind Tunnel (JTWT). A single degree-of-freedom (1-DOF) free-rotation test method was employed as former Japanese ballistic capsules of OREX and HAYABUSA (MUSES-C). The pitching and yawing angular motion of the HTV Return Vehicle (HRV) models were simulated independently. The angular motion depended on the Mach number, Reynolds number, roughness elements, and moments of inertia of the models. A Fourierseries formula was used to fill the gap in the discrete time-series data of angular motion, and the static stability and damping coefficients were calculated algebraically. The obtained damping coefficients of various test conditions are compared and discussed.

In the JAXA 2m x 2m Transonic Wind Tunnel (JTWT), there have been more needs of wind tunnel users for high measurement accuracy to develop aircraft and launch vehicles with high performance. Integration modern test techniques of the JTWT have to be established. Wind tunnel tests with an 80% scaled NASA Common Research Model (CRM) are conducted to validate our results. Errors of balance output due to balance calibration temperature are confirmed. The test section Mach number, the clear tunnel buoyancy, the wall interference, and the upflow angle corrections are integrated and applied to the CRM wind tunnel tests data in the JTWT. Support interference effects with results of CFD with support and CFD without support are investigated. Moreover, our wall interference correction results and support interference effects are compared with wall interference corrections of the NASA National Transonic Facility (NTF) and the NASA Ames 11-ft Wind Tunnel, and support interference effects of the NTF. Thus, these results show that aerodynamic data, which are not affected by wind tunnel, can be estimated more precisely by the application of the balance calibration matrix, fundamental wind tunnel interference corrections, and the support interference correction appropriately.

The JAXA 2m x 2m Transonic Wind Tunnel (JTWT) conducted tests for 80% scaled NASA Common Research Model (CRM). The dynamic data including buffet measurement with strain gauges and dynamic pressure sensors were acquired at 50,000 Hz sampling rate. A prediction of buffet phenomenon is one of important factors to design aircraft. If buffet phenomenon occurs, dynamic bending and torsion moment are measured with wing-root strain gauges. Spectrum analyses are being executed for the strain gauges and dynamic pressure data. It is expected to observe dynamic flow separation at points around where the relation with lift coefficient data and pitching moment coefficient is non-linear. This paper describes overview of the tests and the analysis data.