scholarly journals IMAGE PROCESSING TECHNIQUE FOR SIMULTANEOUSLY MEASURING WATER-SURFACE AND VELOCITY AND IT'S APPLICATION TO OPEN-CHANNEL FLOW OVER CONCAVE BED

2001 ◽  
Vol 45 ◽  
pp. 511-516
Author(s):  
Hitoshi MIYAMOTO ◽  
Tohru KANDA ◽  
Kazumasa OOE
Keyword(s):  
Image Processing ◽  
Channel Flow ◽  
Water Surface ◽  
Open Channel ◽  
Open Channel Flow ◽  
Processing Technique ◽  
Image Processing Technique

scholarly journals Experimental dataset and numerical simulation of floating bodies transport in open-channel flow

2020 ◽  
Vol 22 (5) ◽  
pp. 1161-1181
Author(s):  
Elisabetta Persi ◽  
Gabriella Petaccia ◽  
Stefano Sibilla ◽  
Pilar Brufau ◽  
José Ignacio García-Palacin
Keyword(s):  
Channel Flow ◽  
Water Surface ◽  
Open Channel ◽  
Numerical Models ◽  
Rectangular Channel ◽  
Open Channel Flow ◽  
Body Motion ◽  
Lagrangian Model ◽  
Floating Body ◽  
Floating Bodies

Abstract Numerical models trying to faithfully represent the movement of floating bodies transport in open-channel flow require experimental data for validation. In order to provide an adequate dataset, flume experiments were carried out to analyse the transport of singular and grouped rigid bodies floating on the water surface. Both cylindrical and spherical samples were employed: they were released in a rectangular channel under steady conditions in one-dimensional (plain channel) and two-dimensional (2D) configurations using one rectangular side obstacle, one smooth side obstacle or two rectangular alternate obstacles. The outcomes of the experiments are the planar displacement and the rotation of the samples, which are related to the flow field in the different configurations. The detailed experimental analysis of the floating body motion provides information for the calibration of numerical models simulating floating bodies transport. This dataset is thus employed for the validation of the Eulerian–Lagrangian model ORSA2D_WT, highlighting its strengths and improvable aspects. Similar applications could be carried out with any 2D model which performs the simulation of discrete elements moving on the water surface.

scholarly journals ON A COEXISTENCE SYSTEM OF FLOW AMD WAVES

1966 ◽  
Vol 1 (10) ◽  
pp. 25
Author(s):  
Junzaburo Matsunashi
Keyword(s):  
Channel Flow ◽  
Periodic Motion ◽  
Water Surface ◽  
Open Channel ◽  
Forced Oscillation ◽  
Fixed Bed ◽  
Open Channel Flow ◽  
Experimental Fact ◽  
Incoming Wave ◽  
Mechanical Effects

It is a well known experimental fact that the undulation such as sand-ripples or antidunes are formed on the bed surface composed of fine sand, corresponding to the flow characteristics of open channel flow.O In this case, as the mechanical effects of the bed undulationes stated above, a kind of periodic motion is superposed on the flow, and accordingly the water surface undulates periodically. On the other hand, the mechanical effects of this surface undulationes are surperposed on these undulating bed surfaces as another kind of periodic motion. The wave generated in open sea propagates upstream through an estuary. Accordingly the incoming wave is superposed on the flow stated above as a forced oscillation. Both of these phenomena are in the coexistence system of flow and waves in the open channel flow. In this paper, as the first step to study the subjects stated above, the author treats the problem of the coexistence system in the case when the forced oscillation of water surface is superposed on the open channel flow with fixed bed, and analyzes theoretically and experimentally the mechanical properties of the reciprocal action between flow and waves.

ANALYSIS OF OPEN-CHANNEL FLOW WITH A SIDE CAVITY ZONE BY LES TAKING INTO ACCOUNT OF WATER SURFACE VARIATION

2007 ◽  
Vol 51 ◽  
pp. 655-660
Author(s):  
Ken KADOTANI ◽  
Ichiro FUJITA ◽  
Ryota TSUBAKI ◽  
Takayuki MATSUBARA
Keyword(s):  
Channel Flow ◽  
Water Surface ◽  
Open Channel ◽  
Open Channel Flow ◽  
Surface Variation

A P.I.V. Processing Technique for Directly Measuring Surface-Normal Velocity Gradient at a Free Surface

2005 ◽  
Author(s):  
Tuy N. M. Phan ◽  
Chuong V. Nguyen ◽  
John C. Wells
Keyword(s):  
Free Surface ◽  
Channel Flow ◽  
Velocity Gradient ◽  
Open Channel ◽  
Open Channel Flow ◽  
Processing Technique ◽  
High Mass ◽  
Normal Velocity ◽  
Uniform Compression ◽  
Surface Normal

Compressive surface-normal velocity gradient at a free surface leads to high mass transfer across a free surface. Our research aims to directly measure this velocity gradient at the free surface by proposing an advanced Particle Image Velocimetry (PIV) technique and simultaneously evaluate its applicability. This technique, PIV/IG (Interface Gradiometry), was proposed by Nguyen et al. (2004) to directly measure wall velocity gradient with high S.N.R. Herein, we adapt this technique to measure the compressive surface-normal velocity gradient at the free surface of open channel flow with minimal fluctuation of water surface. We validate this technique in a two-component PIV configuration by synthetic PIV images corresponding to uniform compression, linearly-varying compression, and a velocity field based on DNS data of open channel flow at friction Reynolds number Reτ = 240 and zero Froude number. The results clearly show that this technique works much better than the velocity differentiation method. The effect of template size on the measured value is evaluated.

Sign in / Sign up

Export Citation Format

Share Document