A convective cooling apparatus cools an electronic device including at least one heat-generating component and enclosed in a case having cooling medium such as air or fluid therein. The convective cooling apparatus neither attempts to increase the velocity of flow in the cooling medium nor replaces the cooling medium with other material as prior art cooling apparatus did. Instead, it utilizes the instability which is inherent in the flow of the cooling medium. In the convective cooling apparatus, by using a driver for generating a signal tuned to the characteristic frequency of the flow, a an acoustic vibrator is driven to provide acoustic waves. The acoustic waves induce resonance of flow, which renders the cooling medium vigorously mixed, which, in turn, enhances the heat dissipation from the device.