Heat transfer phenomena are numerically studied with standing waves inside the tubes for stationary and moving sinusoidal wavy walls. Effects of spatial wavelengths (lambda = 1/2, 2/3, 1 and 2 mm), Reynolds number (1-120), frequency (0-60 Hz) and amplitude (1%-20% of tube diameter, d) on heat transfer and pressure drop are studied. For stationary wall case, upon increasing the number of sine waves, the Nusselt number starts to decrease; the associated pressure drop and friction factor increases very rapidly at highest value of amplitude. Heat transfer enhancement characteristics on a moving sinusoidal wavy-walled tube with imposed frequency (0<f<60 Hz) were also examined. The pressure drop has been reduced by 20-80% and heat transfer is enhanced by 30-70% for the entire range of frequency.