The drag force decreases with decreasing of the surface area between the hull and water.
拖曳力的下降，下降的表面积之间的船体和水。
2
Decreasing the particle size is usually conducted by applying a shearing force.
通常使用剪切力减小颗粒粒度。
3
In the compound process of ultrasonic vibration and grain machining, the discontinuous grinding mechanism caused by ultrasonic vibration is the main factor decreasing normal grinding force.