Author(s): Tatemasa Hirata; Kohji Muraoka
Linked Author(s): Tatemasa Hirata
Keywords: No Keywords
Abstract: This paper is concerned with internal seiching motion and resultant mixing event on solid boundary in nearshore. Based on field experiments in Lake Chuzenji, internal seiche caused by wind continues to oscillate as long as several days since its generation. The waveperiod of seiche can be est imated with high accuracy by using Holmboe's model, and waveheight in initial stage of the motion reaches 5 m. Besides, fluid particles near bottom travel in horizontal distance of 43.7 m during a half waveperiod and their maximum speed in horizontal direction rises up to 0.35 cm/s. Mixing on the slope near lakeside is est imated by calculating the difference between two temperature time series recorded vertically at each two points with 0.5 m interval. Mixing event has a tendency to occur at trough region in temperature time series, which corresponds to crest phase of int ernal wave. Vertical thermal profile clearly proves this result that the profile seems to be wavy in thermocline as check line approaches the lakeside. Distortion in thermal structure varies from t ime to time. Mixing zone on vertical scale is limited approximately to 0.5 m distance above the bottom and temperature difference driven by mixing event is as small as 0.2°C.
Year: 1985