Gavin Fields Senior Water Resources Engineer XP Solutions

Transcription

1 Hydraulics 101

2 Gavin Fields Senior Water Resources Engineer XP Solutions

3 Hydraulics 101 Introduction Structures Hydraulic Model Building Q&A

4 XP Solutions Software for modeling wastewater, stormwater, and floods Graphical User Interface (GUI) and analytical engines CAD/GIS type interface and data management tools Graphical reports, maps, animations 1D analytical engine solves the complete St. Venant (Dynamic Flow) equations for gradually varied, one dimensional, unsteady flow 2D analytical engine embedded as xp2d

5 XP-LIVE Webinars This is part of our XP-LIVE educational program Webinars have been recorded and are available at Question/Answer

6 Introduction Hydraulics is the assessment of fluid flows. Where does the water come from?

7 Simulate the flow of water to predict the magnitudes, volumes and dynamics of the flow as it moves down a pipe or via an open channel and floodplain. Aim

8 Water flows downhill

9 General Theory All hydraulic equations are derived from Newton s Second Law of Motion: F=ma The first equation all hydraulic engineers need to be familiar with is the Continuity Equation: Q=VA Continuity maintains mass and therefore volume

10 General Theory Momentum equations then define flow direction The Dynamic Wave equation is the dominant momentum equation Most other momentum equations simplify the Dynamic Wave equation E.g. Kinematic Wave, Chezy and Manning equations

11 Types of Models Steady-State Models Rely on the approximation methods such as Manning s equation for uniform flow typically with a constant inflow Fully Dynamic Models Allow for gradually varied, unsteady flow Allow for variable inflows and boundary conditions

12 Basic differences between pipe flow and open channel flow of an incomprehensible fluid Pipe flow Open channel flow Flow driven by Pressure work Gravity (i.e. potential energy) Flow cross-section Known (fixed by pipe geometry) Unknown in advance because the flow depth is unknown beforehand Characteristic flow parameters Specific boundary conditions Velocity deduced from continuity equation Flow depth and velocity deduced by solving simultaneously the continuity and momentum equations Atmospheric pressure at the flow free surface Chanson, Hubert, The Hydraulics of Open Channel Flow: An Introduction, Second Edition Table 1.1, Page 8.

13 What structures impact on hydraulics? Natural deviations in terrain i.e. channel bends Junctions i.e. inlets, pits, manholes and pipe junctions Physical Structures - Weirs Physical Structures - Orifices Physical Structures - Gates/Valves etc.

14 Weirs a. Sharp crested weir b. Broad crested bottom sill c. Ogee-type weir d. Broad crested weir

15 Broad Crested Weir Demonstration Oregon Institue of Technology Flume Demonstration 2014

16 Vortex Animation Physical Controls

17 Energy equation Losses associated with physical impacts on flow Friction effects Roughness i.e. Manning s n Other Key Aspects

18 Manning s n Overgrown channel n = Grass channel n = Concrete pipe n = Poly pipe n = 0.011

19 Energy and Hydraulic Grade Lines

20 Assess existing conditions Size infrastructure Pipes Man-made channels Pump systems Detention/retention systems Practical Applications

21 Play Video Existing Infrastructure Failure

22 Pipes Manmade Channels Pump systems Detention/retention systems Size infrastructure

23 1D node-link structure 2D surface models 1D-2D integrated models How to build a model

24 Nodes Pits Inlets Catch basins Outlets Junctions Storage Links Bridges Pipes Channels Pumps Orifices, weirs, rating curves 1D node-link structure

25 Node Data Storage Geometry Inflow 1D data requirements

26 Link Data Geometry Flow Losses, e.g. roughness and structure impacts 1D data requirements

27 Inlets / Outlets

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30 2D data requirements Surface 2D grid extents Rain/Inflow Landuse data (including roughness)

31 1D/2D Integrated Model

32 Questions? Comments? Thank you for joining this presentation, Hydraulics 101 By Gavin Fields Contact XP Solutions Americas: Asia Pacific: ausales@xpsolutions.com EMEA: uksales@xpsolutions.com

33 FHWA Hydraulic Design of Highway Culverts

34 Tailwater Effects