An engineering model for countercurrent flow under wind-induced waves and current

Abstract

A general model for the phase-averaged velocity field in wind-induced countercurrent flow is proposed. The influence of waves on the time-averaged velocity is accounted for by introducing a skewness factor in a parabolic eddy viscosity model. The skewness factor represents the net effect of the wavy surface in the engineering model for velocity. The coherent velocity components are described separately by an orbital velocity obtained from linear wave theory and are added to the time-averaged components to give a complete model for the phase-averaged velocity field. The proposed model collapses to the standard model for deep-water conditions, but is also shown to yield the correct behavior for intermediate conditions. Moreover, the bed shear stress, derived from the proposed velocity model, is also shown to be in agreement with experiments.

Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

“…Studies like Baines and Knapp (1965); Cheung and Street (1988); Goossens et al (1982); Komori et al (1993); Kranenburg (1987); Langmuir et al (1938); Longo et al (2012); Sanjou et al (2010); Sanjou and Nezu (2011); Tsanis and Leutheusser (1988); Tsanis (1989); Wu (1975) have reported experimental investigation of wind induced water currents, focusing on both the surface motion and the counter-current flow but without vegetation. Some studies have discussed a simple analytical model of wind set-up by constructing one, two and three dimensional models and engineering models for wind induced counter-current flow but without any vegetation (Bukatov and Zavyalov, 2004;Belcher et al, 1994;Cioffi et al, 2005;Harris et al, 1996;Hunter and Hearn, 1987;Jin and Kranenburg, 1993;Koçyigit and Koçyigit, 2004;Meyer, 2011;Rodi, 1980;Wu and Tsanis, 1995;Yang, 2001;Yang et al, 2008). The role of waves in vegetated system has been considered, but in these cases, the entire wave was imposed on the vegetation primarily to mimic tidal systems so as to study wave attenuation, equivalent bed roughness and friction factor inside aquatic vegetation canopy under wave forcing (Bradley and Houser, 2009;Fonseca and Cahalan, 1992;Hansen and Reidenbach, 2011;Infantes et al, 2012;Kobayashi et al, 1993;Manca et al, 2012;Mendez and Losada, 2004;Riffe et al, 2011;Thomas and Cornelisen, 2003).…”