Centre of Pressure

University of Palestine College of Engineering & Urban Planning Applied Civil Engineering

Experiment 1 Hydrostatic Force and Center of Pressure Lecturer: Dr.H Dr .Has assa sann Ha Hamod moda a

T.A: Eng.. Eman Eng Eman Al. Al.Sw Swai aity ty

1.1 INTRODUCTION This experiment is designed to help you understand how to locate the center of pressure and compute the hydrostatic force acting on a submerged surface.

1.2 Objectives: • To determine experimentally the resultant hydrostatic force (total force) applied on a submerged surface. • To determine the experimental and the theoretical center  of pressure.

1.3 Description of the apparatus:

1.4 Theory: Figure shows the submerged surface viewed from the left side of the tank . The depth of the centroid below the surface of the water is h. The x-y coordinate system has its origin at the centroid. The y-direction position of the center  of pressure, yR,

1.4 Theory:

1.4. Theory:

1.4. Theory:

1.4. Theory:

1.4. Theory:

1.4.1 For Partially Submerged Surfaces:

1.4.2 For Fully Submerged Surfaces:

1.5 Procedure: vPlace

the empty tank on the Bench and position the balance arm on the pivot. vPlace the balance pan in the groove at the end of the balance arm. v Level the tank. vPosition the counterbalance weight until the balance arm is horizontal. v Add a known amount of weight to the balance pan. Pour water into the tank until the balance arm is horizontal again. (Note: it may be easier to overfill then use the drain to level it.) vWhen the arm is level, this means that the force on the vertical face of the quadrant balances out the force due to the added weight. vRead the depth of immersion from the scale on the face of the quadrant. vRepeat the experiment by adding more weights (increments of 50g should work fine) until you have at least two measurements in which the vertical face is completely submerged. vCalculate the magnitudes and locations of the forces for each weight combination. vCompare these locations with the theoretical positions.

1.6 Report requirement: 1-Compute the following: • The total force (Fr) acting on the submerged portion of the surface • The moment (M) of the total force (Fr) at the water surface • The theoretical center of pressure (h” ) • The experimental center of pressure (h”), by summing moments about the fulcrum axis • The percentage of error between the theoretical and experimental values of h”

2- In the results section; discuss results, sources of error, and possible discrepancies with theoretical data.

1.7 RESULTS SHEET:  A.PARTIAL IMMERSION Total weight on arm M grams Depth of Water d mm

force (F) Newton's

h” experimental

h” theory

b

mm

d

mm

L

mm

1.7 RESULTS SHEET: B.FULL IMMERSION Total weight on arm M grams Depth of Water d mm force (F Newton's h” experimental

h” theory

b

mm

d

mm

L

mm