Dissertation > Excellent graduate degree dissertation topics show

The Effect of Vegetation Rigidity on Flow Resistance

Author: WangXiaoYan
Tutor: YanZhongMin
School: Hohai University
Course: Hydraulics and River Dynamics
Keywords: vegetation rigidity ratio of vegetation bending resistance flow resistance flow structure
CLC: TV131
Type: Master's thesis
Year: 2007
Downloads: 190
Quote: 6
Read: Download Dissertation

Abstract


In order to study the mechanism of flow resistance exerted by vegetation in open channel, vegetation rigidity has been researched and a dimensionless number, F, was introduced to describe vegetation ability to resist bending in this paper. Physical experiment, Particle Image Velocimetry (PIV) measurement and numerical simulation were used to study the effect of vegetation rigidity on flow resistance in submerged conditions.In PIV measurement, 2-D data collection techniques were used to gain vector field of flow around vegetation with different vegetation rigidity under similar flow conditions. The result shows that when vegetation exists in channel, flow structure is more complex, with abundant whirlpools signifying violent turbulence. And as the decrease of vegetation rigidity, flow field intends to be stable.In physical experiment, the correlation between F and vegetation drag coefficient, as well as vegetation roughness, were analyzed. The result indicates that, under the same condition of vegetation density and arrangement, when F is smaller than 12.2371, the vegetation behaves absolute erectness and the vegetation roughness coefficient and drag coefficient have no relation with F. When F is larger than 12.2371, the vegetation roughness coefficient and drag coefficient decrease as F increases.In numerical stimulation, flow field, flow velocity distribution and total pressure distribution on vegetation surface were studied around vegetation of three different statuses, i.e. vertical, acclivitous and lying. The result demonstrates that the turbulence effect of vertical vegetation is larger than that of acclivitous vegetation, and much larger than lying vegetation. The pressure on vegetation front surface is larger than that on back surface. And the pressure difference decreases with the lying of vegetation, while viscous force increases.

Related Dissertations

  1. Study on Local Scour Around Spur Dikes on Sand Beds of Yellow River by Model Experiment,TV131.6
  2. Plate-fin heat exchanger gas flow resistance characteristics of the study of the test system,TK172
  3. Research on Medium-term Financial Failure Warning,F275
  4. Large Eddy Simulation of Under-Expanded Supersonic Impinging Jet,O358
  5. The Study on the Mechanism An Experiment of High Pressure Water Jet Slotted,TP69
  6. Coupled Simulation of Flow and Reaction in Reaction and Regeneration System of FCC,TE624.41
  7. Study on Hydrogen Production by Methane Catalytic Decomposition in A Fluidized Bed Reactor,TQ116.2
  8. Dongxiang Copper deep cemented filling system to carry the parameter optimization study,TD853.34
  9. Simulation on the Vortex Shedding Caused by the Cross-flow over Plates in a Narrow Channel,TL334
  10. Study on Hydraulic Characteristics of Central Bar before/after Being Protected,TV133
  11. Analyzing and Investigating Application of Centrifugal Fine-coal Remover in Coal Preparation Plant,TD94
  12. Research and Developing on Fuel Injection Pump with Top Clearance Plunger,TK423
  13. Numerical Simulation and Optimization of Air Distribution of Air Conditioning in a Railway Station,U453.5
  14. Experimental Investigation on the Characteristics of Flow at Low Reynolds Numbers in Mini-channels,V231
  15. Investigation on Flow and Heat Transfer Performance of Longitudinal-Flow Heat Exchanger,TK172
  16. Research of Hydraulic Geometry in Alluvial Channels Based on Extreme Hypotheses,TV143
  17. Flow Resistance Characteristic and Visualization Experiment of Direct Methanol Fuel Cell,TM911.4
  18. PIV Study of Flow Structure in a Stirred Tank,TQ021
  19. Research on the Technology of Disposal of the Sucker-rod Wear in Polymer Flooding Pumping Units,TE933
  20. Biomechanical Study to the Meridian in Traditional Chinese Medicine,R224
  21. Study on Vibro-acoustic Energy Flow of Ship Structure by Vibration Intensity Visualization Technique,U661.44

CLC: > Industrial Technology > Hydraulic Engineering > The basic science of water resources project > Hydraulics > Hydraulic theory, calculation, experiment
© 2012 www.DissertationTopic.Net  Mobile