1 / 87

VIII. Viscous Flow and Head Loss

VIII. Viscous Flow and Head Loss. Contents. Introduction Laminar and Turbulent Flows Friction and Head Losses Head Loss in Laminar Flows Head Loss in Turbulent Flows Head Loss of Steady Pipe Flows Minor Losses Examples. 1. Introduction. Shear stress due to fluid viscosity.

judith
Télécharger la présentation

VIII. Viscous Flow and Head Loss

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. VIII. Viscous Flow and Head Loss

  2. Contents • Introduction • Laminar and Turbulent Flows • Friction and Head Losses • Head Loss in Laminar Flows • Head Loss in Turbulent Flows • Head Loss of Steady Pipe Flows • Minor Losses • Examples

  3. 1. Introduction

  4. Shear stress due to fluid viscosity

  5. D’Alembert Paradox

  6. For real fluid flows Head Loss

  7. Head Loss: • Losses due to friction • Minor Losses • entrance and exit • sudden change of cross sections • valves and gates • bends and elbows • ……

  8. 2. Laminar and Turbulent Flows

  9. Reynolds’ Experiment

  10. Laminar Flows: • Movement of any fluid particle is regular • Path lines of fluid particles are smooth Turbulent Flows: • Movement of any fluid particle is random • Path lines of fluid particles are affected by mixing

  11. Transition from Laminar to Turbulent Flow: • for different fluid • for different diameter of pipe

  12. Head Loss due to laminar and turbulent flows

  13. Laminar Flows: Turbulent Flows:

  14. Critical Condition Reynolds Number

  15. 3. Friction and Head Losses

  16. Momentum Equation A : area of the cross-section P: wetted perimeter

  17. Hydraulic radius

  18. Darcy-Weisbach equation

  19. 4. Head Loss in Laminar Flows

  20. 5. Head Loss in Turbulent Flows

  21. Mean flow and fluctuation

  22. Mean flow and fluctuation

  23. Basic Equations of Turbulent Flows:

  24. Basic Equations of Turbulent Flows:

  25. Reynolds’ Average

  26. Reynolds’ Average

  27. Reynolds Stresses

  28. Reynolds Stresses Mean flux of horizontal momentum: Equivalent Shear Stress:

  29. Reynolds Equations:

  30. Theory of Mixing Length

  31. Logarithmic Velocity Distribution

  32. 6. Head Loss of Steady Pipe Flows

  33. Logarithmic Velocity Distribution

  34. Logarithmic Overlap Layer

  35. Logarithmic Velocity Distribution in a Pipe

More Related