Fluid dynamics is a topic that is sometimes covered in high school physics but is always covered in college physics courses. Calculating the fluid flow is a routine calculation that can be done in a few simple steps based on Bernoulli's equation. Learn calculate the volume of fluid flow per second.
Instructions
Calculating Volume per Second
1. Find the velocity of the fluid in meters per second. If the problem does not give you the speed, you must find it yourself.
2. Calculate the cross-sectional area in meters squared of the pipe or duct through which the fluid is moving. For example, plumbing pipes are cylindrical in shape, and a cross-section would look like a circle. So, the cross-sectional area would be the square of the radius of the pipe multiplied by pi. A pipe with a radius of 1 cm would have a cross-sectional area of 0.000314 square meters. Be sure to convert the dimensions to meters before calculating.
3. Multiply the velocity of the fluid by the cross-sectional area of the pipe or duct to find the volume of fluid flow per second. A fluid traveling at 5m per second through a pipe of 1cm diameter would be moving at a rate of 0.00157cm per second.
Finding Velocity after Change in Area
4. Find the cross-sectional area of the pipe at two different sections and the velocity of the fluid through the pipe in one section. For instructions on calculating the cross-sectional area, see Step 2 of the previous section. Make sure the area is in square meters and the velocity is in meters per second.
5. Multiply the cross-sectional area of the pipe by the velocity of the fluid through that section of the pipe.
6. Divide the product in the previous step by the area of the pipe where you want to find the velocity. This quotient is the speed of the fluid through the second area of the pipe in meters per second.
Calculating Velocity from Height, Pressure and Density
7. Identify the pressure, height and density of the fluid at two different places along the pipe. One of these two places should be the place where you would like to find the velocity of the fluid. Call this place "point A." The other place will be called "point B." Make sure the pressure is in Pascals, the height is in meters and the density is in kilograms per cubic meter.
8. Subtract the pressure at point A from the pressure at point B.
9. Multiply the number 9.8 by the height and the density at Point A. Repeat this process for Point B.
10. Subtract the product for Point A in the step above from the product for Point B in the step above.
11. Multiply the number one half by the density of the fluid and the square of the velocity at point B if it is given.
12. Add each of the numbers from Step 2, Step 4 and Step 5 in this section.
13. Divide the number found in Step 6 by the product of one half and the density of the fluid.
14. Take the square root of the number found in Step 7. This is the velocity of the fluid through point A in meters per second.
Tags: cross-sectional area, velocity fluid, area pipe, fluid through, meters second, cross-sectional area pipe, density fluid