TY - JOUR
TI - Thermal effects influencing measurements in a supersonic blowdown wind tunnel
AU - Vuković Đorđe S
AU - Damljanović Dijana B
JN - Thermal Science
PY - 2016
VL - 20
IS - 6
SP - 2101
EP - 2112
PT - Article
AB - During a supersonic run of a blowdown wind tunnel, temperature of air in the  test section drops which can affect planned measurements. Adverse thermal  effects include variations of the Mach and Reynolds numbers, variation of  airspeed, condensation of moisture on the model, change of characteristics of  the instrumentation in the model, et cetera. Available data on thermal  effects on instrumentation are pertaining primarily to long-run-duration wind  tunnel facilities. In order to characterize such influences on  instrumentation in the models, in short-run-duration blowdown wind tunnels,  temperature measurements were made in the wing-panel-balance and main-balance  spaces of two wind tunnel models tested in the T-38 wind tunnel. The  measurements showed that model-interior temperature in a run increased at the  beginning of the run, followed by a slower drop and, at the end of the run,  by a large temperature drop. Panel-force balance was affected much more than  the main balance. Ways of reducing the unwelcome thermal effects by  instrumentation design and test planning are discussed.