development and calibration of a center of pressure apparatus

Description

ABSTRACT

The Centre of Pressure Apparatus has been designed to determine the static thrust exerted by a fluid on a submerged surface and allow comparison of the measured magnitude and position of this force with simple theory. A fabricated quadrant is mounted on a balance arm, which pivots on knife-edges. The knife-edges coincide with the centre of arc of the quadrant. Thus, of the hydrostatic forces acting on the quadrant when immersed, only the force on the rectangular end face gives rise to a moment about the knife-edges. The balance arm incorporates a balance pan for the weights supplied and an adjustable counterbalance. This assembly is mounted on top of an acrylic tank, which may be leveled by adjusting screwed feet. An indicator attached to the side of the tank shows when the balance arm is horizontal. Water is admitted to the top of the tank by a flexible tube and may be drained through a cock in the side of the tank. The water level is indicated on a scale on the side of the quadrant.

TABLE OF CONTENT

Title page                                                          i

Certification                                                        ii

Dedication                                                         iii

Acknowledgement                                              iv

Abstract                                                             v

Table of content                                                 vi

CHAPTER ONE

1.0     INTRODUCTION

1.1     BACKGROUND OF THE STUDY

1.2     AIM OF THE PROJECT

1.3     OBJECTIVES OF THE STUDY

1.4     SCOPE OF THE STUDY

1.5     PURPOSE OF THE PROJECT

1.6     SIGNIFICANCE OF THE STUDY

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF HYDROSTATIC PRESSURE
• HISTORICAL BACKGROUND OF HYDROSTATIC PRESSURE
• HYDROSTATIC EXAMPLE (DAM)
• HISTORICAL USAGE FOR SAILBOATS
• REVIEW OF MOVEMENT OF CENTER OF PRESSURE FOR AERODYNAMIC FIELDS

CHAPTER THREE

METHODOLOGY

• SYSTEM DESCRIPTION
• EQUIPMENTS AND APPARATUS
• OBJECTIVES OF THE EXPERIMENT
• METHOD
• TECHNICAL DATAPROCEDURE

CHAPTER FOUR

• RESULT
• CALCULATION

CHAPTER FIVE

• CONCLUSION

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

The center of pressureis the point where the total sum of a pressure field acts on a body, causing a force to act through that point. The total force vector acting at the center of pressure is the value of the integrated vectorial pressure field. The resultant force and center of pressure location produce equivalent force and moment on the body as the original pressure field. Pressure fields occur in both static and dynamic fluid mechanics. Specification of the center of pressure, the reference point from which the center of pressure is referenced, and the associated force vector allows the moment generated about any point to be computed by a translation from the reference point to the desired new point. It is common for the center of pressure to be located on the body, but in fluid flows it is possible for the pressure field to exert a moment on the body of such magnitude that the center of pressure is located outside the body.

1.2                                                   AIM OF THE PROJECT

The main aim of this work is to setup an apparatus that is used in determining the centre of pressure and the thrust on a body immersed in a fluid basically water.

1.3                                             OBJECTIVE OF THE PROJECT

1. To determine the hydrostatic thrust acting on a plane surface immersed in water.
2. To determine the position of the line of action of the thrust and to compare the position determined by experiment with the theoretical position.

1.4                                                   SCOPE OF THE STUDY

From this experiment we are able to measure the moment due to the total fluid thrust on a wholly, or partially, submerged plane surface to be directly measured and compared with theoretical analysis. The plane area may be tilted relative to the vertical so that the general case may be studied. The water is contained in a clear Perspex quadrant, the cylindrical sides of which have their central axes coincident with the axis about which the turning moments are measured. The total fluid pressures on the secured surfaces therefore exert no moment about this pivot, the only moment being due to the fluid pressure on the plane test surface. This moment is simply measured by weights suspended from a level arm.

1.5                                              PURPOSE OF THE PROJECT

The purpose of this work is:

1. Determination of force due to hydrostatic pressure
2. Determination of Center of pressure

1.6                                           SIGNIFICANCE OF THE STUDY

1. Very efficient
2. Rigid construction

• Easy to operate

1. Long lasting

CHAPTER FIVE

5.1                                                   CONCLUSIONS

At the end of this work, the theoretical and practical aspect of this work was carried out, all the result was calculated using both theoretically and experimentally. This study allows students to measure the moment due to the fluid (hydrostatic) thrust on a fully or partially submerged plane. The plane works in either a vertical or inclined (angled) position. Students then compare their measurements with theoretical analysis.

The equipment consists of a vertical panel that holds a clear plastic quadrant, to which students add water. The quadrant has engraved lines to help students keep the plane in a vertical or angled position.

The cylindrical sides of the quadrant have their central axis coincidental with the moment measurement axis. The total fluid pressures on these curved surfaces therefore exert no moment about this pivot. Therefore, the moment is only due to the fluid pressure on the plane test surface. Students measure this moment using weights suspended from a level arm. A scale on the panel of the apparatus shows the head of water.