DENSITY RECONSTRUCTION FROM LASER SCHLIEREN SIGNAL IN SHOCK-TUBE EXPERIMENTS

Using a diffraction approach the convolution-type integral equation fo r the laser schlieren signal created by an arbitrary disturbance at lo w pressure. where refractive index of disturbance is close to unity, i n a shock tube (thin optical layer) has been deduced. In the equation electric circuit relaxation processes were taken into account by a res ponse function. The equation was solved with the aid of the regulariza tion method worked out for ill-posed problems. The density structures of the strong shock waves in air have numerically been reconstructed f rom experimental data ranging shock wave Mach number of M-s = 20-30, a nd P-0 = 10-30 Pa.