Instantaneous water surface and bed scour profiles using video image analysis

1998 ◽  
Vol 25 (4) ◽  
pp. 662-667 ◽  
Author(s):  
R Balachandar ◽  
J A Kells
Keyword(s):  
Image Analysis ◽  
Flow Field ◽  
Water Surface ◽  
Surface Profile ◽  
Steady Flows ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Water Surface Profile ◽  
Bed Scour

In steady open-channel flow, the use of a conventional point gauge to obtain the water surface profile yields reasonably accurate results. However, in unsteady and quasi-steady flows, the point gauge is not of much use. Furthermore, in flow fields where there is significant bed scour, it is often of interest to the hydraulic engineer to obtain the instantaneous bed scour profile during the scouring process. In most quasi-steady flows involving bed scour, the water surface profile continuously readjusts itself in response to the changes in the bed profile. To carry out a proper analysis of the entire flow field, it is necessary to obtain both the instantaneous water surface and the corresponding bed scour profiles. The development of a nonintrusive video image analysis procedure to simultaneously obtain the water surface and bed scour profiles in a two-dimensional flow field is presented in this paper. A computer program entitled PROSCAN has been developed to extract the water surface and bed scour profiles from digitized video images of the flow field. The use of PROSCAN is demonstrated by obtaining the instantaneous water surface and bed scour profiles for a two-dimensional flow field downstream of a sluice gate.Key words: image analysis, software development, water surface profile, bed scour profile, scour dynamics.

scholarly journals Two-dimensional flow field distribution characteristics of flocking drainage pipes in tunnel

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 139-148
Author(s):  
Shiyang Liu ◽  
Xuefu Zhang ◽  
Feng Gao ◽  
Liangwen Wei ◽  
Qiang Liu ◽  
...  
Keyword(s):  
Flow Field ◽  
Field Distribution ◽  
Rapid Development ◽  
Maximum Velocity ◽  
Distribution Characteristics ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Laboratory Test Results ◽  
Transverse Distance ◽  
Two Dimensional Flow

AbstractWith the rapid development of traffic infrastructure in China, the problem of crystal plugging of tunnel drainage pipes becomes increasingly salient. In order to build a mechanism that is resilient to the crystal plugging of flocking drainage pipes, the present study used the numerical simulation to analyze the two-dimensional flow field distribution characteristics of flocking drainage pipes under different flocking spacings. Then, the results were compared with the laboratory test results. According to the results, the maximum velocity distribution in the flow field of flocking drainage pipes is closely related to the transverse distance h of the fluff, while the longitudinal distance h of the fluff causes little effect; when the transverse distance h of the fluff is less than 6.25D (D refers to the diameter of the fluff), the velocity between the adjacent transverse fluffs will be increased by more than 10%. Moreover, the velocity of the upstream and downstream fluffs will be decreased by 90% compared with that of the inlet; the crystal distribution can be more obvious in the place with larger velocity while it is less at the lower flow rate. The results can provide theoretical support for building a mechanism to deal with and remove the crystallization of flocking drainage pipes.

Extension of the Prandtl–Batchelor theorem to three-dimensional flows slowly varying in one direction

2010 ◽  
Vol 654 ◽  
pp. 351-361 ◽  
Author(s):  
M. SANDOVAL ◽  
S. CHERNYSHENKO
Keyword(s):  
Flow Field ◽  
Small Parameter ◽  
Order Approximation ◽  
Three Dimensional ◽  
Inviscid Limit ◽  
Two Dimensional ◽  
Leading Order ◽  
Dimensional Flow ◽  
Two Dimensional Flow

According to the Prandtl–Batchelor theorem for a steady two-dimensional flow with closed streamlines in the inviscid limit the vorticity becomes constant in the region of closed streamlines. This is not true for three-dimensional flows. However, if the variation of the flow field along one direction is slow then it is possible to expand the solution in terms of a small parameter characterizing the rate of variation of the flow field in that direction. Then in the leading-order approximation the projections of the streamlines onto planes perpendicular to that direction can be closed. Under these circumstances the extension of the Prandtl–Batchelor theorem is obtained. The resulting equations turned out to be a three-dimensional analogue of the equations of the quasi-cylindrical approximation.

scholarly journals Use of heat as tracer to quantify vertical streambed flow in a two-dimensional flow field

2012 ◽  
Vol 48 (10) ◽  
Author(s):  
Hamid Roshan ◽  
Gabriel C. Rau ◽  
Martin S. Andersen ◽  
Ian R. Acworth
Keyword(s):  
Flow Field ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow

On two-dimensional inviscid flow in a waterfall

1965 ◽  
Vol 22 (2) ◽  
pp. 359-369 ◽  
Author(s):  
N. S. Clarke
Keyword(s):  
Asymptotic Expansion ◽  
Flow Field ◽  
Froude Number ◽  
Inviscid Flow ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Free Streamlines ◽  
Two Dimensional Flow ◽  
Boundary Geometry

This paper is concerned with the two-dimensional flow in a free waterfall, falling under the influence of gravity, the fluid being considered to be incompressible and inviscid. A parameter ε, such that 2/ε is the Froude number based on conditions far upstream, is defined and considered to be small. A flowline co-ordinate system is used to overcome the difficulty that the boundary geometry is not known in advance. An asymptotic expansion based on ε is constructed as an approximation valid upstream and near the edge, but singular far downstream. Another asymptotic expansion, based upon the thinness of the fall, is constructed as an approximation valid far downstream, but failing to satisfy the conditions upstream. The two expansions are then matched to give a solution covering the whole flow field. The shapes of the free streamlines are shown for a number of values of ε for which the solutions are seemingly valid.

Fluid-Solid Coupling Analysis on the 2-Dimentional Flow Field of Internal Mixer

2011 ◽  
Vol 221 ◽  
pp. 592-597 ◽  
Author(s):  
Hai Xia Zhao ◽  
Hui Guang Bian
Keyword(s):  
Flow Field ◽  
Two Dimensional ◽  
Coupling Analysis ◽  
Structure Interaction ◽  
Dimensional Flow ◽  
Field Simulation ◽  
Pressure Area ◽  
Two Dimensional Flow ◽  
Internal Mixer ◽  
Better Than

Two-dimensional flow field simulation of two-wing synchronous rotor and four-wing synchronous rotor mixer were studied and the simulation computation of the fluid-structure interaction in a real sense were realized with FEM software. It can be concluded that the synchronous four-wing rotor can produce the pressure area for mixing rubber better than the synchronous two-wing rotor under the same conditions, and therefore, refining capacity and efficiency of the synchronous four-wing rotor are bigger than that of the synchronous two-wing rotor.

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