Direct numerical simulation of carbon-dioxide gas absorption caused by turbulent free surface flow

The turbulent behavior of liquid and gas flows at a free surface is not ver y well understood in comparison with that of the motions at the solid bound ary. In the present study, the DNS for the turbulent free surface how with a shear wind has been carried out by means of a coupled gas-liquid flow sol ution procedure, i.e., multi-interface and advection and reconstruction sol ver (MARS) developed by one of the authors. Henry's law is applied to the e valuation of a saturated gas concentration at the free surface caused by th e carbon-dioxide gas absorption. Resulting from the present DNS of turbulen t free surface flow with carbon-dioxide gas transfer at the gas-water inter face, the mean and root-mean-square distributions of velocity, pressure and concentration and their fluctuations throughout both the gas and liquid Ro w fields are obtained and compared with the experimental data. Finally, an exchange coefficient of carbon-dioxide gas at the turbulent free surface es timated in this study is in good agreement with the existing experimental a nd sea-measurement data. (C) 2001 Elsevier Science Inc. All rights reserved .