Aerodynamic force measurement using 3-component accelerometer force balance system in a hypersonic shock tunnel

The accurate prediction of force is very important in the present scenario of aerodynamic force measurement. The high accuracy of force prediction during calibration facilitates a better accuracy of force measurement in aerodynamic facilities like shock tunnels and wind tunnels. The present study describes the force prediction in an accelerometer force balance system using support vector regression (SVR). The comparison of SVR with the existing force prediction techniques namely, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) has also been carried out. The accelerometer force balance used in the current experimentation consists of a tri-axial accelerometer to measure the response on an aluminium hemispherical model on the application of force. The impulse forces were applied along the axial, normal and azimuthal directions. The forces were predicted using the accelerations obtained from the tri-axial accelerometer. SVR method was able to predict the forces quite accurately as compared to ANFIS and ANN. However, SVR has the advantage over ANFIS and ANN in that it is independent of the magnitude of the training and testing data. It is capable of an accurate prediction of forces with any magnitude of training and testing data, unlike ANFIS and ANN.

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Measurement of aerodynamic forces for missile shaped body in hypersonic shock tunnel using 6-component accelerometer based balance system

Shock Waves ◽

10.1007/978-3-540-85168-4_102 ◽

2009 ◽

pp. 637-642

Author(s):

S. Saravanan ◽

G. Jagadeesh ◽

K.P.J. Reddy

Keyword(s):

Shock Tunnel ◽

Aerodynamic Forces ◽

Shaped Body ◽

Balance System ◽

Hypersonic Shock ◽

Hypersonic Shock Tunnel

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Impulse Force Balance for Ultrashort Duration Hypersonic Test Facilities

Shock and Vibration ◽

10.1155/2015/803253 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8

Author(s):

P. Singh ◽

V. Menezes ◽

K. J. Irimpan ◽

H. Hosseini

Keyword(s):

Impulse Response ◽

Aerodynamic Force ◽

Delta Wing ◽

Shock Tunnel ◽

Force Balance ◽

Test Model ◽

Impulse Response Functions ◽

Response Functions ◽

Test Assembly ◽

Hypersonic Shock

This paper presents the measurement of side force, pitching, and yawing moments on a model, using an accelerometer force balance, in a short duration hypersonic shock tunnel. The test model is a blunt-nosed, flapped delta wing, mounted on a support sting through a force balance. The flexible rubber bushes constituting the balance allow the model to float freely on the sting during the test. The accelerometers were located in the model to record accelerations in the directions of interest. The model was tested in shock tunnel at Mach 8 at different angles of incidence with the freestream. Dynamic calibration of the test assembly was carried out for the acquisition of impulse response functions for the above components of force and moments, using an impulse hammer. The convolution technique was applied to derive the impulse response functions. The accelerometer outputs from the model in the hypersonic freestream were processed using the respective impulse response functions to derive the unknown aerodynamic force and moments. The newly adopted convolution technique has been found very effective for data reduction from accelerometer force balances developed for shock tunnel applications.

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A comparison of accelerometer and piezofilm-based force balances for hypersonic shock tunnels

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410019845200 ◽

2019 ◽

Vol 233 (14) ◽

pp. 5310-5320

Author(s):

Soumya Ranjan Nanda ◽

Vinayak Kulkarni ◽

Niranjan Sahoo ◽

Viren Menezes

Keyword(s):

Fuzzy Inference System ◽

Fuzzy Inference ◽

Force Measurement ◽

Force Balance ◽

Balance Theory ◽

Inference System ◽

Balance System ◽

Cone Model ◽

Neuro Fuzzy ◽

Hypersonic Shock

A blunt double-cone model, equipped with a three-component accelerometer or piezofilm-based force balance system, is tested in the IITB-Shock Tunnel at 0 º and 10 º angle of inclinations during force measurement experiments. Conventional accelerometer force balance theory and soft computing-based adaptive neuro fuzzy inference system have been adopted to recover the axial and normal forces. In order to arrive at the time varying forces, these balances are calibrated using impulse hammer tests at single or multiple points. Necessity of multipoint calibration has also been demonstrated during recovery of forces for both the balances. Genetic algorithm in conjunction with adaptive neuro fuzzy inference system has been implemented herein to train the system for force prediction. Encouraging agreement has been noted between the predictions made using accelerometer force balance theory and adaptive neuro fuzzy inference system-based recovery of forces from accelerometer and piezofilm balances. Thus, present studies not only provide the methodology for calibration and implementation of piezofilm based force measurement, but also recommend its usage in short duration impulse facilities.

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