Laser Doppler anemometry using the photon correlation method of signal processing has been used to measure a velocity field in which sinusoidal fluctuations generated acoustically are superimposed on a steady flow. A stochastic model has been developed for the form of the correlation function, and it is shown to be consistent with previous models for a steady flow and for sinusoidal fluctuations in an acoustic field. Measurements have been made of the velocity field associated with steady flow in a tube with a superimposed acoustic field, the results were shown to be consistent with the theoretical predictions.