Aerodynamic characteristics of a delta wing in hypersonic flow

Abstract

In space programs there has been a marked interest lately in the construction of a high-altitude aerospace vehicle (ASV) capable of making shuttle flights to earth orbits for the delivery of various payloads (including spaceship units and components). The various geometries and assembly configurations of such a vehicle are a topic of ongoing discussion among developers at conferences and in print, ground tests are being performed on models, and mathematical model computations are in progress.The actual conditions of flow past an ASV cannot be fully modeled by ground-based wind tunnel research, so that mathematical modeling plays a fundamental role in determining the vehicle aerodynamic characteristics, and experimental data are used to verify the mathematical models. The Hermes aerodynamic research program utilizes test configurations and test regimes discussed in [1]. Considering the complexity of the experiments, it is important to perform measurements under various conditions (on different test facilities using several different methods) so that reliable data can be obtained.Here EXPERIMENTAL APPARATUS AND PROCEDUREThe investigations at Moo = 20.6 are carried out in the T-327 nitrogen wind tunnel at the Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences (ITPM SO RAN) [2]. The apparatus has a working section in the form of a pressure chamber, and flow is generated by means of a conical nozzle with an orifice diameter of 220 mm. Off-model three-component strain gauges equipped with an innovative cooling system, are used for the measurements. The ranges of the measurements are as follows: longitudinal force X = 0 to 0.5 N; normal force Y = -0.5 N to 0.5 N; longitudinal (pitching) moment M z = -0.05 N.m to 0.05 N.m. According to the results of numerous static calibration runs, the measurement error limits expressed in percentages of the measurement ranges are 0.5% for X, 0.5% for Y, and 0.25% for M z. More detailed information about the balance and the procedure for balance experiments in the T-327 may be found in [3, 4], and the results of control model tests (a sphere, a truncated cone, and AGARD models HB-1 and HB-2) are given in [5].The experiments at Mo. = 8.0 are carried out in the T-236 wind tunnel at ITPM SO RAN. The ranges of the modeled parameters are Mo, = 6-16 and (Reynolds number at unit length) Re 1 = (50-700)-105 m -I. A resistance heater capable of reliably heating the air in the prechamber to 800 K is used for the operating regimes Moo = 6-10. The apparatus has an Eifel chamber and is equipped with interchangeable profiled nozzles having orifice diameters of 200 ram, which impart a high degree of uniformity to the flow core. The overall dimensions of the tested models are 50 • 50 • 150 ram.An off-model three-component balance using silicon resistance strain gauges has been developed and fabricated for the T-326 wind tunnel, along with the analog balance of the kind used in the T-327, but engineered for large loads [6]. The balances are equipped with...