NMOHEMS probe is one kind of miniature expendable probe carried by UAV. The numerical simulation model was developed based on the hybrid grid and turbulent model to analyze the effects of the draft cavity, contraction section and empennage on the dropping of NMOHEMS probe. The relationships between lgRe and drag coefficient of six shape probes and limited velocities at the same mass were obtained, and the comparison showed that the influence of different shapes on the results of numerical simulation couldn' t be ignored. The draft cavity and contraction section reduced the drag, and contraction section had more effect. The empennage increased the drag. At 2.3 to 3.8, the drag coefficients of six shape probes were different and decreased rapidly. And at 3.8 to 5.1, the drag coefficients were close and decreased slowly. Because the volume of NMOHEMS probe was small and the velocity of dropping was slow, the influence of shape had to be analyzed when the drag coefficients and limited velocities were numerically simulated.%NMOHEMS探头是一种由无人机运载的小型投掷式探头,采用混合网格技术结合湍流模型,建立了探头下沉运动的数值计算方法,分析了导流腔、收缩段及尾翼对探头下沉运动的影响;通过6种外形探头在不同雷诺数下的阻力系数和相同质量下的极限速度对比,发现探头外形对其下沉运动数值计算的结果影响较大;其中导流腔和收缩段均具有明显的减阻作用,且收缩段的影响更大,而尾翼具有一定的增阻作用;lgRe在2.3～3.8时,6种外形探头的阻力系数差别较大,随着雷诺数的增加,阻力系数均迅速减小;lgRe在3.8～5.1时,6者的阻力系数比较接近,虽仍然保持减小趋势,但变化趋于缓慢.NMOHEMS探头的体型较小,下沉速度较慢,对其下沉运动进行数值计算时,必须考虑外形对数值计算结果的影响.
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