Relation Among Conductivity Characteristic of Ship Wake, Seawater Temperature and Bubble Distribution

Physical and mathematical models are established in order to analyze and calculate the influence of seawater temperature and bubble distribution on conductivity characteristic of ship wake. For the bubble wake with vertical temperature gradient, it is supposed that the bubbles are arbitrarily or uniformly distributed between the two poles of a probe that is used to detect the conductivity of the wake. The laws, on the basis of which the conductivity difference value δK between background seawater and wake is jointly influenced by seawater temperature, bubble radius, bubble density and bubble distribution mode, are obtained. The results show that δK will rise with increasing seawater temperature or bubble radius or bubble density no matter what bubble distribution is when seawater temperature ranges from 10 to 16 ℃, bubble radius is less than 100 μm and bubble density varies from 2.16×10⁸ to 6.4×10¹⁰/m³. Under given seawater temperature, bubble radius and bubble density, the δKs respectively corresponding to arbitrary bubble distribution and uniform bubble distribution are far different, the latter is about 2.6 times of the former.