Reorientation of Hydrometeors in Aircraft Accelerated Flow

Abstract

The drag force, instantaneous canting angle and response characteristics are discussed for large hydrometeors in horizontally accelerated airflow. Comparisons of calculated canting angles are made with data from an aircraft precipitation spectrometer (Bringi) by assuming an airflow disturbance based on probe geometry. It is concluded that the accelerated airflow is the likely cause of an intrinsic canting angle for raindrops of about 15° but that the force is too weak to appreciably affect the axis ratio. No intrinsic canting was found for graupel.