Physics Help Forum Fluid Dynamics

 Sep 12th 2017, 02:05 PM #1 Junior Member   Join Date: Sep 2017 Posts: 1 Fluid Dynamics Hi, I have an assignment in my Physics class and I don't know where to start in solving these two problems. I just know I have to use Bernoulli's Equation and Torricelli's Theorem but I don't know how to apply it. :/ Can someone help me? 1. What is the pressure change in methyl alcohol (SG = 0.791) flowing a 4.0 cm diameter pipe to a 1.5 cm diameter pipe if the velocity in the larger pipe is 0.40 m/s? 2. Water flows steadily from an open tank. The elevation of point 1 is 10 m and the elevation of point 2 is 2 m. The cross-sectional area at point 2 is 0.0480 m^2 . The area of the tank is very large compared with the crosssectional area of the pipe. Find the gauge pressure at point 2
Sep 12th 2017, 04:00 PM   #2
Senior Member

Join Date: Apr 2015
Location: Somerset, England
Posts: 708
 Originally Posted by wonhallyu Hi, I have an assignment in my Physics class and I don't know where to start in solving these two problems. I just know I have to use Bernoulli's Equation and Torricelli's Theorem but I don't know how to apply it. :/ Can someone help me? 1. What is the pressure change in methyl alcohol (SG = 0.791) flowing a 4.0 cm diameter pipe to a 1.5 cm diameter pipe if the velocity in the larger pipe is 0.40 m/s? 2. Water flows steadily from an open tank. The elevation of point 1 is 10 m and the elevation of point 2 is 2 m. The cross-sectional area at point 2 is 0.0480 m^2 . The area of the tank is very large compared with the crosssectional area of the pipe. Find the gauge pressure at point 2
A good way to start this would be to write down Bernoulli's Theorem and Torricelli's theorem and see which of the variables you can put values to from the information given and which variable gives the answer to the question.

Can you do this?

Note that question 2 is incomplete since it does not describe what points 1 and 2 represent.

I am guessing that point 1 is the free surface in the tank and point 2 is the outlet.

 Tags dynamics, fluid