ES 202 Fluid and Thermal Systems Lecture 9 Application of Bernoulli s Equation Pipe Flow 12 19 2002 Assignments Reading Cengel Turner Section 12 3 12 4 Optional C T Section 11 5 good stuff Homework 9 12 12 4C 12 9C in Cengel Turner Supplementary problem dimensional analysis on pipe flow Definition of Reynolds number 9 homework problems altogether due on Monday after Christmas holiday Road Map of Lecture 9 Comments on Quiz 1 Application of Bernoulli s equation lift on airfoil tennis ball The Torricelli experiment Modified Bernoulli s equation Concept of viscosity Comments on Quiz 1 What should you expect Question 1 perfect balance between pressure force and gravity static equilibrium Question 2 The cause of buoyancy is the same regardless the density of the immersed object Buoyancy is NOT due to difference in density but difference in pressure Honor code is strictly observed I mean it Reinforce My Teaching Philosophy Learning happens both inside and outside the classroom Inside classroom interactive participation Outside classroom office hours review sessions Lift on Airfoil and Tennis Ball Airfoil destroy the flow symmetry between the lower and upper surfaces show visualization which flow region can cannot be analyzed by Bernoulli s equation Spin on a tennis ball what does the spin do to the tennis ball the dimples on a golf ball are for a different purpose The Torricelli Experiment Schematic of experiment Area A1 H V Describe the fluid motion Area A2 What is the pressure at the exit What is the maximum exit velocity The Bent Torricelli Experiment What will happen if a 90o bend is added to the tank exit H V How high can the water column go up Do you expect the water column reaches the height you just found Explain your answer Modified Bernoulli s Equation What if fluid friction causes some losses in the system can I still apply the Bernoulli s equation Recall the conservation of energy concept from which we approach the Bernoulli s equation Remedy introduce a head loss factor One Major Reason for the Losses Fluid friction also termed Viscosity basketball tennis ball demonstration exchange of momentum at the molecular scales no slip conditions at the solid surface imagine thin layers of fluid moving relative to one another the two train analogy stress strain relation in a Newtonian fluid Stress viscosity X strain rate Description of supplementary homework du dy Merry Christmas and Happy New Year
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