ANALYTICAL STUDY AND EMPIRICAL RELATIONS FOR THE OBLIQUE AND NORMAL SHOCK-WAVES IN REAL AIR

The analytical solution of shock-waves in real air is obtained by the use of the shock-wave governing equations, which have a general validi ty and the best available state equation of real air. The results obta ined from the analytical solution have an excellent accuracy, but they need a great deal of calculation time. These accurate results of the analytical solution are approximated by explicit empirical relations h aving mathematical forms similar to the ideal gas shock-wave ones, but with new, numerically calculated parameters (coefficients and exponen ts). From the comparison of the empirical results with the analytical ones, the relative error is obtained less than 0.1%. The whole procedu re is applied for the general case of the oblique shock-wave in a regi on with practical significance. The normal shock is obtained as a limi ting case of the oblique shock corresponding to specific geometrical c onditions. (C) 1997 Elsevier Science Ltd.