Recent development in oceanographical observational instruments enables us to come into touch with oceanographical microstructure processes directly. Observational evidence tells us that double diffusive convection plays an important role in such processes like mixing, transport of various properties, both vertically and laterally. In this article, we put emphasis on such processes, and try to review double diffusive convection in oceanography briefly. In § 1 the importance of the study of double diffusive convection in oceanography is presented. In § 2 the occurrence, vertical mass transport and stability of double diffusive convection are discussed. In § 3 the behavior of lateral intrusion driven by double diffusive convection is discussed. In § 4 we try to interpret the role of double diffusive convection in vertical mixing processes. In the final section, we consider future possibility of the study of double diffusive convection.

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A numerical method employing a finite-element method is adopted for an investigation of peristaltic pumping in which all the wave amplitude, the wall-wave slope, and the Reynolds number are large. The fluid mechanics of peristaltic mixing and transport are studied in detail by analyzing the reflux and the trapping phenomena. The results show that the inertia effect of the fluid and the effect of large wall slope enhance the backward flow from the narrowest region of the channel. The appearance of the reflux depends upon the Reynolds number as well as the wavenumber (mean channel width/wavelength).

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著者は先に, 風速計用熱線の空間的分解能から見た実効長さは, 無次元長さが3程度以下では幾何学的な長さの2/ 3程度になることを示したが, それは速度変動振幅が熱線の中央で最大になる分布の場合に就いてであった.今回はそれを拡張し, 速度変動は空間的に正弦波の振幅分布をしているが出現する位置は無作為として, 熱線で測定するパワースペクトルの期待値を求めた.パワースペクトル測定値が熱線の長さと速度変動の波長の比が大きくなると減少する割合は熱線の無次元長さが小さい場合には小さく, この意味での熱線の実効長さはここでも幾何学的長さの約2/ 3に等しい.

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