Tiêu đề 2 Hydrostatic Pressure.pdf ✅

HGE 2: Hydrostatic Pressure 1. Hydrostatic Pressure Pressure refers to the force per unit area acting normal to the area. P = F A Consider a column of fluid with cross-sectional area A, pressure at top P1, and pressure at bottom P2. The total force at the bottom is equal to F1 = F2 P1A + W = P2A P1A + γhA = P2A Therefore, P2 − P1 = γh Pascal’s law states that the intensity of pressure acting at a point in a fluid is the same in all directions. The classifications of pressure are: • Atmospheric Pressure (Patm) – refers to the absolute pressure measured at sea level under normal conditions. The standard value for atmospheric pressure is 101.325 kPa or 14.7 psi. Another way this value is expressed is 760 mmHg which comes from the barometric reading at sea level under standard temperature and pressure. • Gauge Pressure (Pg) – refers to the intensity of pressure measured above or below the atmospheric pressure. Pg = ∑γh • Absolute Pressure (Pabs) – the total pressure experienced at a point. Pabs = Pg + Patm As this is an absolute value, its lowest possible value is zero in a state of vacuum.