A Balance for Measurement of Yaw , Lift and Drag on a Model in a Hypersonic Shock Tunnel
Lift and Drag on a lifting model with typical control surfaces, in a hypersonic impulse facility. The model used in the present study is a blunt-nosed triangular plate attached with flaps. The experiments were carried out at a freestream Mach number of 8 in a hypersonic shock tunnel, with air as the test gas, where the test time was about 1.2 milliseconds. The experiments were repeated at different angles of incidence of the model and the coefficients of Yawing moment (C Y), Lift (C L) and Drag (C D) were deduced based on the acceleration signals obtained from the balance. Measured values of the moment and force coefficients were compared with the theoretical results predicted using the Newtonian theory.
Three-component force balance for flows of millisecond duration
The authors investigate the feasibility of a new type of multiple-component force balance for measurements on models in hypervelocity hows of millisecond duration. The balance extends the concept of the single component stress-wave force balance to measurement of axial force, normal force, and pitching moment. Numerical modeling of the performance of the balance shows that coupled deconvolution techniques can be used to decouple the signals from axial strain measurements in the balance to determine the applied loads. Experiments performed in the T4 free-piston shock tunnel on a sharp cone at incidence indicate that the prototype balance performs satisfactorily, forces being measured to within 11% of their theoretical values, and the location of the line of force being measured to within 2.1% of the theoretical location as a fraction of model chord.
Aerodynamic Force Measurements in the VKI Longshot Hypersonic Facility
Measurements of aerodynamic forces and moments on reentry bodies are performed in the VKI Longshot hypersonic facility, using a sting-mounted strain gauge balance. Inertial corrections are applied to compensate the effect of inevitable model vibrations. This involves the measurement of model accelerations, using miniature sensors. Inertial corrections are optimized, taking into account accelerometers transverse sensitivity effects, time lags, signal filtering or smoothing, and tuning for the inertia of the vibrating masses.