field contouring meaning in English

野外勾画等高线

The flows in the case of different reduced frequencies are computed respectively for two blade profiles . by comparing the time curves of relative parameters in oscillating cascades and the flow field contours under different conditions , it is indicated that the reduced frequency is an important factor to determine whether the blade flutter happens or not
针对两种叶型分别计算了不同折合频率下的流场，通过比较振动叶栅相关参数随时间变化的曲线及流场云图，表明折合频率是决定叶片颤振与否的重要因素。