可以为初学UDF的人提供简单的udf程序文件，并且通过解释能够更好地了解udf的运行原理(Simple udf program files can be provided for beginner UDFs, and explanations can better understand how udf works.)

定义了一个用于控制扭转和弯曲周期运动的udf程序，用于计算fluent中动边界案例。(A UDF program is defined to control the periodic motion of torsion and bending, which is used to calculate the dynamic boundary case in fluent.)