The paper presents predictions for the infrasonic attenuation coefficient in the clouds of Venus at altitudes of 50–60 km, where instrumented balloons will likely be deployed. The acoustic wavenumber is obtained by modifying the model of Baudoin, Coulouvrat, and Thomas [J. Acoust. Soc. Am. 130(3), 1142–1153 (2011)] to account for typical Venus cloud composition. A two-phase system, consisting of polydisperse aqueous–H₂SO₄ liquid droplets with a trimodal size distribution and their vapors is considered. Assuming sulfuric acid as the main condensable species, the low-frequency cloud attenuation coefficient is dominated by the evaporation/condensation of H₂SO₄. It ranges from $2\times {10}^{-5}$ dB/km at 10 mHz to 0.1 dB/km at 10 Hz, exceeding that of the dry atmosphere by up to 2 orders of magnitude. Varying the cloud density by $\pm 50\%$ changes the attenuation by $-35\%/+100\%$ at 1 mHz and $\pm 50\%$ at 10 Hz. The same variation in the acid vapor diffusion coefficient causes attenuation changes from $-20\%/+70\%$ at 1 mHz to $+25\%/-40\%$ at 10 Hz. As the evaporation coefficient of H₂SO₄ (presently poorly constrained) is varied from 0.01 to 1, the attenuation drops from ${10}^{-4}$ dB/km to $4\times {10}^{-6}$ dB/km at 10 mHz and increases from ${10}^{-3}$ dB/km to $2\times {10}^{-2}$ dB/km at 10 Hz.

中文翻译：

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在金星的中下部云中吸收次声。

本文提出了对金星云在50–60 km高度处的次声衰减系数的预测，其中可能会部署仪表气球。声波数是通过修改Baudoin，Coulouvrat和Thomas的模型获得的。co Soc。上午。130（3），1142–1153（2011）]来解释典型的金星云组成。考虑一个两相系统，该系统由具有三峰尺寸分布的多分散H ₂ SO ₄水滴及其蒸气组成。假设硫酸是主要的可冷凝物质，则低频云的衰减系数主要由H ₂ SO ₄的蒸发/冷凝决定。范围从$2\times {10}^{-5}$10 mHz时的dB / km至10 Hz时的0.1 dB / km，比干燥大气高出2个数量级。通过改变云密度$\pm 50％$ 改变衰减 $-35％/+100％$ 在1 mHz和 $\pm 50％$在10 Hz 酸蒸气扩散系数的相同变化会导致衰减变化$-20％/+70％$ 在1 mHz至 $+25％/-40％$在10 Hz 当H ₂ SO ₄的蒸发系数（目前受约束程度较弱）从0.01变为1时，衰减从${10}^{-4}$ dB /公里至 $4\times {10}^{-6}$ dB / km在10 mHz时从 ${10}^{-3}$ dB /公里至 $2\times {10}^{-2}$ 10 Hz时为dB / km。