Abstract
There is plenty of experimental evidence that the propagation of an ultrasonic wave in a nematic liquid crystal affects the director n , which represents the average molecular orientation, thus producing detectable optical effects. There have been several attempts to explain these observations on the basis of a coherent variational theory. We present here a general theory for nematoacoustics that incorporates flow effects. An explicit application of the proposed theory to a simple computable case is given in order to estimate phenomenological parameters involved in the theory and by using available experimental data.