Determination of Impingement Forces on a Flat Plate with the Control Volume Method

1. Setting the facility

1. Make sure that there is no flow in the facility.
2. Connect the positive port of the pressure transducer to the plenum pressure tap ().
3. Leave the negative port of the pressure transducer open to the atmosphere ().
4. Record the transducer's conversion factor from Volts to Pascals ().
5. Record the jet exit width.
6. Record the plate span.
7. Record the force balance's conversion constants from Volts to Newton (horizontal force: ; vertical force: ).
8. Setup the data acquisition system to sample at a rate of 100 Hz for a total of 1000 samples (i.e. 10s of data).
9. Mount the impact plate on the force balance and adjust its outputs to zero.

2. Recording the data

1. Set the angle of the plate to 90^o (see Figure 2 for reference).
2. Turn the flow facility on.
3. Record the reading of the pressure transducer in Volts, which corresponds to the pressure difference between the Plenum and the atmosphere ().
4. Record the force data using the data acquisition system.
5. Multiply the acquired values (in Volts) by the force conversion factors ( and ) and enter the results in table 1.
6. Turn the flow facility off.
7. Change the angle of the plate.
8. Repeat steps 2.2 to 2.6 for the following angles:

Figure 2 . Experimental setting. (A): Detail of intake system to pressurize the plenum at pressure . (B): discharge side with impingement plate. (C): Detail of discharge slit. Please click here to view a larger version of this figure.

3. Data Analysis

1. Calculate the normal force measured by the balance using equation(11) and record it in table 1.
2. Determine the theoretical value of the normal force from equation (10) and record it in table 1.
3. Calculate the disagreement between the two values as a percent.

Table 1 . Basic parameters for experimental study.

Parameter	Value
Jet nozzle width (W)	19.05 mm
Plate span (L)	110.49 cm
Transducer calibration constant (m_p)	141.3829 Pa/V
Balance horizontal coefficient (m_x)	22.2411 N/V
Balance vertical coefficient (m_y)	4.4482 N/V