Scalar Transfer Mechanisms at the Sheared Air-Water Interface : Estimation of Scalar Transfer Rate

剪切空气-水界面处的标量传递机制：标量传递率的估计

基本信息

批准号：
14102016
负责人：
KOMORI Satoru
金额：
$ 64.81万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (S)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2006
项目状态：
已结题

项目摘要

It is of great importance to investigate scalar (heat and mass) transfer mechanism across the air-sea interface in order to improve the reliability of predictions for global warming. However, previous sub-models used in a general circulation model for predicting heat and mass transfer velocities across the air-sea interface have been based on the simple assumption that the transfer velocities are proportional to wind velocity over the ocean surface. This rough assumption reduces the reliability of the sub-models. The aim of this study is, therefore, to clarify the scalar transfer mechanism across the sheared air-water interface from the fluid-mechanical point of view and to develop reliable models for the scalar transfer velocity that truly reflects the physical processes involved.The effects of wind speed, fetch, swell, surface contamination, thermal stratification, entrained bubbles, dispersing droplets and rainfall on the mass transfer across the air-water interface have been invest … More igated by carrying out both laboratory experiments and numerical simulation. The results show that the mass transfer velocity k_L, is not simply proportional to the wind speed and it has a kink in the middle wind speed region. The mass transfer velocity is well correlated with the frequency of the appearance of the surface-renewal eddies, since the mass transfer across the sheared air-water interface is controlled by the surface-renewal eddies. The effect of fetch on k_L is compensated when the free-stream wind speed is used as a wind parameter. Both swell and surface contaminants reduce the mass transfer but the thermal stratification in the water flow does not affect the mass transfer because of strong wind-driven turbulence. The entrained bubbles due to intense wave breaking in the high wind speed region significantly promote the mass transfer but the effect of dispersing droplets is negligibly small. The rainfall enhances the mass transfer across the air-water interface and the promotion effect is well described by the momentum flux of rainfall. The details of the results should be refereed to our published articles. Less

为了提高全球变暖预测的可靠性，研究标量（热量和质量）转移机制非常重要。但是，在通用循环模型中使用的以前的子模型用于预测整个空气界面的热量和传质速度，这是基于简单的假设，即传递速度与海面上的风速成正比。这种粗略的假设降低了子模型的可靠性。因此，这项研究的目的是从流体机械的角度阐明剪切空气水界面的标量转移机制，并为标量转移速度的可靠模型开发出可靠的模型，真正反映了实际反映的物理过程。风速，提取，swelt，swell，fetch，swell，swell，swell，表面污染，表面污染，热量，热量，播放的速度，播放的效果，又有落水量，降落在落下，降落在降落中，降落在降落中，降落降落，降落降落，通过进行实验室实验和数值模拟来进行。结果表明，质量转移速度K_L不仅与风速成正比，并且在中间风速区域有扭结。大传递速度与表面更新涡流的外观频率很好地相关，因为跨剪切空气水界面的传质受到表面续订涡流的控制。当自由流风速用作风参数时，获取对K_L的影响得到补偿。膨胀和表面污染物都减少了传质，但是由于强风驱动的湍流，水流中的热分层不会影响传质。由于高风速区域的强烈波动而引起的气泡显着促进传质，但分散液滴的效果却忽略不计。降雨增强了整个空气水界面的传质，促进效应通过降雨量的动量通量很好地描述了促进效应。结果的详细信息应转介我们发表的文章。较少的