REFLECTION AND REFRACTION OF WAVES AT THE BOUNDARY OF A NON-VISCOUS POROUS SOLID SATURATED WITH SINGLE FLUID AND A POROUS SOLID SATURATED WITH TWO IMMISCIBLE FLUIDS

Abstract

THE PHENOMENON OF REFLECTION AND REFRACTION IS STUDIED AT THE WELDED INTERFACE BETWEEN TWO DIFFERENT POROUS SOLIDS. ONE IS SATURATED WITH SINGLE NON-VISCOUS FLUID AND OTHER IS SATURATED WITH TWO IMMISCIBLE VISCOUS FLUIDS. THE INCIDENCE OF PF, PS OR SV WAVE THROUGH POROUS SOLID SATURATED WITH NON-VISCOUS FLUID RESULTS IN THE THREE REFLECTED WAVES AND THE FOUR WAVES REFRACTED TO POROUS MEDIUM SATURATED WITH TWO IMMISCIBLE VISCOUS FLUIDS. FOR THE PRESENCE OF VISCOSITY IN PORE-FLUIDS, THE WAVES REFRACTED TO CORRESPONDING MEDIUM ATTENUATE IN THE DIRECTION NORMAL TO THE INTERFACE. IT IS ALSO REVEALED THAT FOR THE POST-CRITICAL INCIDENCE OF PS WAVE, THE REFLECTED PF AND SV WAVES BECOMES EVANESCENT AND FOR THE POST-CRITICAL INCIDENCE OF SV WAVE, THE REFLECTED PF WAVE BECOMES EVANESCENT. WHILE, THE OCCURRENCE OF CRITICAL INCIDENCE IS NOT OBSERVED FOR THE INCIDENCE OF PF WAVE. THE RATIOS OF AMPLITUDES OF REFLECTED AND REFRACTED WAVES TO THAT OF INCIDENT WAVE ARE EXPRESSED THROUGH A NON-SINGULAR SYSTEM OF LINEAR ALGEBRAIC EQUATIONS. THESE AMPLITUDE RATIOS ARE USED FURTHER TO CALCULATE THE SHARES OF DIFFERENT SCATTERED WAVES IN THE ENERGY OF INCIDENT WAVE. FOR A PARTICULAR NUMERICAL MODEL, THE ENERGY SHARES ARE COMPUTED FOR INCIDENT DIRECTION VARYING FROM NORMAL INCIDENCE TO GRAZING INCIDENCE. THE CONSERVATION OF ENERGY ACROSS THE INTERFACE IS VERIFIED. EFFECTS OF NON-WET SATURATION OF PORES, FREQUENCY OF WAVE AND POROSITY ON THE ENERGY PARTITIONS ARE DEPICTED GRAPHICALLY AND DISCUSSED.