Airflow and sound induced by disk rotation in DVD drives. Part II: Visualization and simulation for noise prediction

This paper explores the airflow and sound induced by high-speed disk rotation in digital versatile disk (DVD) drives to predict aeroacoustic noise characteristics. As a preliminary experimental work in this context, a particle image velocimetry technique has been conducted for airflow visualization and flow-field identification. The central part of the paper describes the impact on the numerical prediction of the airflow-induced sound pressure inside the DVD drive by use of a generalized function theory based on the Ffowcs Williams-Hawkings equation for computational aeroacoustics. The baseline drive is a DVD-ROM 4xwith Ω = 7200 rpm. A flow simulation has been performed to obtain the flow velocity and pressure distributions around the disk surface for use in noise prediction. Noise directivity is discussed to identify noise patterns and mechanisms inside the DVD drive.