The widespread applications of fluid mechanics and hydraulics in civil engineering include transportation of fluids in pipes and in open channels, as well as flow measurement for both pipes and open channels. These areas of application use a variety of calculations for design and for analysis.Pipe Flow CalculationsLiquids and gases are transported through pipes for a wide variety of applications. Engineers need to be able to calculate i) the pipe size needed for a given flow rate and available pump head, ii) the head loss due to a given flow rate through a pipe of known size, or iii) the the flow rate through a specified pipe with a given head loss. These articles present the calculation procedure and the equations to be used for each of these types of calculations, as well as example calculations. There are articles on the use of Darcy-Wiesbach/friction factor calculations and on the use of the Hazen Williams formula. Information is also presented on the use of Excel spreadsheets for pipe flow calculations.Pipe Flow Calculations 1 - The Entrance Length for Fully Developed FlowPipe Flow Calculations 2 - Reynolds Number for Determining Laminar or Turbulent FlowPipe Flow Calculations 3 - The Friction Factor and Frictional Head LossPipe Flow/Head Loss/Friction Factor Calculations with Excel SpreadsheetsExcel Formulas to Calculate Water Flow Rates for Different Pipe SizesUniform Open Channel Flow CalculationsFor open channel flow, a free liquid surface is open to atmospheric pressure, so the driving force for flow is gravity, rather than a pressure difference as in pipe flow. Examples of open channel flow include flow in rivers and streams, in storm sewers, in arroyos and irrigation channels, and in man-made open channels such as those used in wastewater treatment plants. Uniform open channel flow occurs when a constant flow rate passes through a channel with constant bottom slope, constant surface roughness, and constant shape and size. These articles center on the use of the Manning equation for uniform open channel flow, including calculation of the hydraulic radius, determination of the flow rate in a given channel at a given depth of flow and determination of the normal depth of flow, for a given channel and flow rate. There are articles on natural channel calculations and articles that emphasize calculations for man-made channels.Introduction to the Manning Equation for Uniform Open Channel Flow CalculationsCalculation of Hydraulic Radius for Uniform Open Channel FlowCalculation of Normal Depth for Open Channel FlowCalculating Uniform Open Channel Flow/Manning Equation Solutions with Excel SpreadsheetsUse of the Manning Equation for Open Channel Flow in Natural ChannelsDetermining the Manning Roughness Coefficient for a Natural ChannelManning Equation Calculations for Partially Full Pipe FlowHow to Use the Manning Equation for Storm Sewer CalculationsOpen Channel Flow MeasurementWeirs and flumes are the most common devices for measuring flow rate in open channels. These articles include information about sharp crested, rectangular and V-notch weirs, broad crested weirs, and Parshall flumes. The information includes descriptive material, diagrams, equations, example calculations, and discussion of the use of Excel spreadsheets for the calculations.Open Channel Flow Measurement 1: Introduction to the Weir and FlumeOpen Channel Flow Measurement with V-Notch WeirsOpen Channel Flow Measurement with Rectangular, Sharp-Crested WeirsOpen Channel Flow Measurement with Parshall FlumesOpen Channel Flow Measurement with Broad Crested WeirsExcel Spreadsheets for V-Notch Weir Flow Measurement CalculationsExcel Spreadsheets for Rectangular Weir Flow Measurement CalculationsExcel Spreadsheets for Parshall Flume Flow Measurement CalculationsExcel Spreadsheets for Broad Crested Weir Flow Measurement CalculationsPipe Flow MeasurementA widely used type of flow measurement device for pipe flow is the differential flow meter, including flow nozzle, orifice, and venturi meters. These meters use a constriction in the flow area to increase the fluid velocity and thus decrease the fluid pressure. The amount of pressure decrease can then be measured and used to calculate the flow rate. Descriptive material, equations, and example calculations are included for flow nozzle, orifice, as well as venturi meters, along with information about pitot tubes, rotameters, and magnetic flow meters.The Orifice, Flow Nozzle, and Venturi Meter for Pipe Flow MeasurementUse ISO 5167 to Find the Orifice Discharge Coefficient for an Orifice Flow MeterExcel Templates for Venturi and Orifice Flow Meter CalculationsHow to Measure Fluid Velocity with a Pitot TubeMeasurement of Pipe Flow Rate with a Rotameter Flow MeterPipe Flow Measurement with a Magnetic Flow MeterHydraulic Jumps and Supercritical Open Channel FlowHydraulic jumps occur in order to make a transition from supercritical flow to subcritical flow on a channel that isn't steep enough to maintain supercritical flow. The articles in this section provide background information about subcritical, critical, and supercritical flow, about hydraulic jump calculations, and about calculation of parameters like critical depth and critical slope for open channel flow.Subcritical, Critical and Supercritical Open Channel FlowOpen Channel Flow Basics - Hydraulic Jump CalculationsUse of Excel Formulas for Hydraulic Jump CalculationsCalculation of Critical Depth and Critical Slope for Open Channel FlowFluid Mechanics FundamentalsFundamental fluid mechanic principles are useful in a variety of ways. For example, the Ideal Gas Law can be used to calculate the density of air and other gases at different tempertures and pressures. The equations and methods of calculating drag force due to fluid flow past an immersed object can provide insight into the reason why the dimples in golf balls make the golf balls go farther than smooth balls would.What is the Ideal Gas Law?Drag Force for Fluid Flow Past an Immersed ObjectHow Do Golf Ball Dimples Reduce Air Resistance and Make Balls Go Farther?The Continuity Equation and Common Fluid Flow Rate ParametersUse the Ideal Gas Law to find the Density of Air at Different Pressures and Temperatures

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