Jet Impinging on an Inclined Plate

Source: Ricardo Mejia-Alvarez and Hussam Hikmat Jabbar, Department of Mechanical Engineering, Michigan State University, East Lansing, MI

The goal of this experiment is to demonstrate how a fluid flow exerts forces on structures by conversion of dynamic pressure into static pressure. To this end, we will make a plane jet impinge on a flat plate and will measure the resulting pressure distribution along the plate. The resultant force will be estimated by integrating the product between the pressure distribution and appropriately defined area differentials along the surface of the plate. This experiment will be repeated for two angles of inclination of the plate with respect to the direction of the jet and two flow rates. Each configuration produces a different pressure distribution along the plate, which is the result of different levels of conversion of dynamic pressure into static pressure at the plate's surface.

For this experiment, pressure will be measured with a diaphragm pressure transducer connected to a scanning valve. The plate itself has small perforations called pressure taps that connect to the scanning valve through hoses. The scanning valve sends the pressure from these taps to the pressure transducer one at a time. The pressure induces mechanical deflection on the diaphragm that the pressure transducer converts into voltage. This voltage is proportional to the pressure difference between the two sides of the diaphragm.

1. Setting the facility

1. Make sure that there is no flow in the facility.
2. Set the instruments according to the schematic in figure 2.
3. Adjust the plate to the desired angle . Record this value in table 1.
4. Measure the jet nozzle width W. Record this value in table 1.
5. Measure the plate span L. Record this value in table 1.
6. Zero the pressure transducer.
7. Note the calibration constant of

Figure 4 shows four sets of results obtained for the plane jet impinging on a plate at two different angles and two different flow rates. In fact, since the low-pressure side of the transducer is opened to the receiver, its readings correspond only to the overpressure , which are in fact the points shown in Figure 4.

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The experiments featured herein demonstrated the interplay of pressure and velocity to generate loads in objects by means of conversion of dynamic pressure into static pressure. These concepts were demonstrated with a plane jet impinging on a flat plate at two different angles and two different flow rates. The experiments clearly demonstrated that the load is highest at the stagnation point, where all the dynamic pressure is converted into static pressure, and its magnitude decreases as the level of conversion from dynam

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