A COMBINED DATA PROCESSING METHOD ON WATER IMPACT FORCE MEASUREMENT

作     者：ZHAO Meng-hua CHEN Xiao-peng ZHAO Meng-hua;CHEN Xiao-peng

作者机构：School of MechanicsCivil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China 

出 版 物：《Journal of Hydrodynamics》 (水动力学研究与进展B辑（英文版）)

年 卷 期：2012年第24卷第5期

页      面：692-701页

核心收录：

学科分类：08[工学] 082601[工学-武器系统与运用工程] 0826[工学-兵器科学与技术] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0701[理学-数学] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.11172241) the Innovation Foundation of Aerospace Science and Technology of China the National High Technology Research and Development Programs of China(863 Program,Grant No.2012AA011803) 

主　　题：water impact force measurement image processing low-pass filter sub-pixel edge detection 

摘      要：A combined method is proposed to determine the water entry acceleration at a low impact velocity through image processing. The procedure includes： （1） a sequence of images for water impact are recorded by a high speed camera, （2） the sub-pixel image processing method is employed to calculate the displacement with an accuracy on the ＂sub-pixel＂ level, （3） the acceleration of the object is acquired by differentiating the displacement twice and with results being further filtered by a carefully designed low-pass Butterworth filter. A theoretically based analysis is conducted for designing the parameters of the low-pass filters. It is shown that the water entry can be regarded as a procedure with a slowly changing velocity. The method is validated with the standard sinusoidal motion and the water entry of a sphere. This approach could be considered as an auxiliary method during the early-stage study of the water entry, and it could be further applied to some complicated circumstances, like the water entry of spinning spheres.