 This was followed by Lev P. Gor'kov's work which generalised the field into the Gor'kov potential, the mathematical foundation for acoustic levitation which is still in widespread use today.The Gor'kov potential is limited by its assumptions to spheres with a radius significantly less than the wavelength, the typical limit is considered to be one tenth of the wavelength.Further analytical solutions are available for simple geometries however, to extend to larger or non-spherical objects it is common to use numerical methods, particularly the finite element method or the boundary element method.