Time-varying phase offset for DSP sine wave?

I'm trying to simulate a receiving array that tracks a beacon's location by the relative phases received by several antennas/receivers. Since the beacon moves relative the the array, the values of phase change as a function of time.

How can I implement a sinusoid with time-varying phase offset in a discrete time system in simulink? I know there is a variable for phase offset, but can it take on a time-varying value?

Thanks!