Abstract: The present invention discloses a method and system for a wind stress coefficient expression by comprehensively considering impacts of an average wind speed, a fetch and a water depth, and relates to the field of wind-wave-current numerical simulation studies. Based on a wind-wave-current coupling interaction mechanism in lakes, oceans and other waters, two dimensionless numbers that can represent a wind-wave-current interaction strength: a fetch Froude number and a fetch Reynolds number, are constructed, a form of a wind stress coefficient expression with an undetermined coefficient is established, and then the undetermined coefficient is obtained by using a nonlinear regression method with reference to experimental and measured data to obtain a final wind stress coefficient expression.

Abstract: The disclosure claims a magnetizing device and method for preparing magnetized water for dust fall of an underground coal mine. The device is formed by a plurality of magnetic drums in a parallel connection with connecting elbows in a “U”-shaped arrangement manner. Each magnetic drum consists of an external magnet, an internal magnet, a hollow pressure pipe, a spiral blade, a screen magnet cover, a connecting steel column, a pressure pipe, a closed nut and a flange plate. According to the disclosure, the internal and external magnets are arranged on a spiral flow channel consisting of the hollow pressure pipe, the spiral blade and the pressure blade by means of an alternating arrangement, thereby building an efficient magnetization environment combined by pulse cutting magnetization and spiral turbulence, enabling that the water for dust fall flowing through is magnetized continuously and efficiently.