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Your search keyword '"Non-uniform flow"' showing total 3 results
Start Over Descriptor "Non-uniform flow" Language japanese
3 results on '"Non-uniform flow"'

1. 非一様流れの中で粒子が受ける履歴力の数値解析.

Author

深田 利昭

Subjects
NON-uniform flows (Fluid dynamics), COMPUTER simulation, AXIAL flow, TURBULENCE, COMPUTATIONAL fluid dynamics
Abstract

The history force on a particle depends on background flow and needs to be studied to understand dilute particleladen turbulence. In this study, we numerically investigate the history force on the translating sphere in some nonuniform flows in which the undisturbed streamlines are curved, over a range of the particle Reynolds number being 5 ≤ Rep ≤ 40. For the axisymmetric straining flow, the applicability of the history force model which is based on the result of the uniform flow is highly influenced by the direction of the straining. For the non-axisymmetric shear flows, the history force perpendicular to the particle translating velocity agrees with the model for 5 ≤ Rep ≤ 10. In conclusion, the limited applicability of the history force model is clarified for some non-uniform flows. [ABSTRACT FROM AUTHOR]

Published
2018
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2. A water quality model of an urban stream

Subjects
River, non-uniform flow, BOD, simulation, water quality
Abstract

A simulation model is presented to describe water quality in a river flowing through an urban area. The model is composed of a submodel calculating the non-uniform flow and a diffusion submodel. The diffusion submodel, dispersion can describe a variation of particulate and dissolved BOD as well as dissolved oxygen. In the submodel, dispersion, setting of particles, decomposition and reaeration are considered as single processes. Accompanied with the submodel calculating the non-uniform flow, prediction of water quality is possible with varying flow rate. The application of this model to the Kaki River at Nagaoka showed a successful representation of BOD and DO in the river.

Published
1988

3. 実船プロペラ性能の近似計算法について : 相当無限翼数プロペラ計算法の改良

Subjects
non-uniform flow, torque, propeller, thrust, performance of propeller
Abstract

The propeller of a ship generally operates in a wake behind the hull. Then the propellerreceives complicated and mutual interference with a hull and a rudder. We usually dividethe ship into three parts i.e. the hull, the propeller and also the rudder, when we considerthe problem of the ship propulsive performance. The propeller occupies an important partof ship propulsion in the sense that it affects the hull and the rudder largely. Moreover apropeller operates in such a non-uniform flow, and then we require a numerical methodthat the calculation of the propeller performance is easy and the computing time is short.And such a computation method should be able to estimate well the forces and the moments acting on the propeller and also the velocity field around it finely.For this purpose, there are some computation methods based on "equivalent infinitely-bladed propeller".However, the value of a section drag coefficient of a propeller bladewas taken generally too large in these methods. Therefore these methods are inappropriate when the scale effect or the characteristics of an actual ship propeller are estimated.In this paper, in order to take into account the viscous, effect, the authors attempt toimprove the numerical method based on the Ueda-Yamazaki's theory of "equivalent infinitely-bladed propeller". And then results are compared with the experimental values.An application to an actual ship propeller is also examined.

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