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CE 230-Engineering Fluid Mechanics. Fluid flow. Flowing fluids. Static versus flowing fluid Objectives of the part of course Basic concepts and definitions. Types of flow. Steady versus unsteady Uniform versus no uniform 1-D versus multi-D Laminar versus turbulent.
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CE 230-Engineering Fluid Mechanics Fluid flow
Flowing fluids • Static versus flowing fluid • Objectives of the part of course • Basic concepts and definitions
Types of flow • Steady versus unsteady • Uniform versus no uniform • 1-D versus multi-D • Laminar versus turbulent
Development of flow pattern • Why not solve problem? • Flow visualization analog and experimental methods • Streamlines, streaklines and pathlines
Volume flow rate, Q • Q = ΔV/ Δt = dV/dt • Calculating Q if velocity is constant • Q=∫ v.dA • Mass flow rate
Example 5.3 Find flow rate and average velocity in the pipe (R=5 cm), if the velocity distribution is given by: Note that U [cm/s] r [cm]
Example 5.3 Find flow rate and average velocity in the 5 m wide channel. Given: d = 2 m and maximum velocity = 3 m/s.
Example Find flow rate and average velocity in the triangular channel. Given: maximum velocity = 6 ft/s.
Material derivative and Acceleration • Total acceleration • Local acceleration • Convective acceleration
Example (p 4-26) Determine local, convective and total accelaration at x=0.5L and t= 3 s
Derivation of Euler’s equation Consider a cylindrical fluid element being accelerated in direction l and neglect viscous effects Use equilibrium equation Σ F = m a
Let’s take l along a stream line call s (i.e. flow along a streamline) But Therefore
Assume steady flow and drop subscript But last term is Substituting back, dividing by γ (assuing incompressible fluid) and integrating wrt s we get
Bernoulli equation One form of BE is Note assumptions made No losses Flow along streamline Steady flow incompressible
4.44 Consider water jet shown. Calculate h, if the water velocity as it exists the nozzle is 20 ft/s
Find flow rate of water given pipe diameter at 2 =10 cm pipe diameter at 1 =30 cm 5 m 60 cm Hg