Influence of Small Water Surface Perturbations on the Reaeration Process

• Published in: Journal of environmental engineering (New York, N.Y.) Vol. 140; no. 3
• Main Authors: Nguyen, Manh Tuan, Appan, Adhityan, Tan, Danielle S, Tan, Soon Keat
• Format: Journal Article
• Language: English
• Published: American Society of Civil Engineers 01.03.2014
• Subjects: Coefficients; Diffusivity; Environmental engineering; Mathematical models; Oxygen; Oxygen transfer; Perturbation methods; Ripples; Technical Papers
• ISSN: 0733-9372; 1943-7870
• DOI: 10.1061/(ASCE)EE.1943-7870.0000791

AbstractThis paper aims to develop a general reaeration model for water bodies subject to small surface perturbation, such as ripples that may be induced by wind, waves, and surface current. A test rig was specially designed and fabricated to study the influence of waves on the reaeration process. The wave frequency varied from 0.125 Hz to 0.425 Hz for various wave heights, H, ranging from 0.15 cm to 1.5 cm. Based on the findings of the experimental study, the authors developed a modified film model and introduced a diffusive film-layer thickness δD as the characteristic length scale for the reaeration process. The thickness of the diffusive film layer may be determined readily in one of two ways: (1) as the ratio between the molecular diffusivity of dissolved oxygen and the measured oxygen transfer coefficient; and (2) estimated using its established functions with other concentration boundary layers proposed by various researchers. The modified film model was found to unify the present experimental data and published data.