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利用涡结构对光波通过高速流场的光学传输特性进行建模,就必须进行涡结构的识别。文中提出一种涡结构识别方法,首先把密度场转换的折射率场等效为具有丰富纹理信息的灰度图像,进而对其进行多小波分解,计算每次分解的小波基系数的熵值,利用阈值判定低熵的为大涡的小波基系数,高熵的为小涡的小波基系数。计算机仿真结果表明,该方法能有效地进行涡结构识别,为基于涡结构的光学传输精确建模奠定了基础。
Using the vortex structure to model the optical transmission characteristics of a light wave through a high velocity flow field, vortex structures must be identified. In this paper, a method of vortex structure identification is proposed. Firstly, the refractive index field converted from density field is equivalent to a gray image with rich texture information, and then multi-wavelet decomposition is performed on it to calculate the entropy of the wavelet coefficients of each decomposition. The wavelet coefficient of low-entropy large-eddy is judged by the threshold, and the high entropy is the wavelet base of small vortex. Computer simulation results show that this method can effectively identify vortex structures and lay a foundation for accurate modeling of optical transmission based on vortex structures.