Optimization of a magnetic linear transducer actuator using computational fluid dynamics

Ultrasound transducer arrays represent the current standard for medical ultrasound imaging applications. Despite this, the development of low-cost imaging systems is typically limited to single element wobbler transducers. We have developed a novel single element transducer system that is able to replicate the function of expensive linear arrays. This system uses a Lorentz force linear motor to mechanically sweep a single element transducer along a linear path. In order to optimize our system´s operating characteristics for high speed imaging applications, we have performed a fluid dynamics analysis of the drag generated as a result of the transducer motion. Analytical and finite element models are derived for the motion of a rectangular cylinder through a confined channel. Our analysis reveals that small changes to the actuator housing geometry can drastically reduce drag, allowing us to achieve higher imaging frame rates. In addition, we predict the formation of an alternating vortex street that may introduce an additional source of vibration.