Hydraulics and Fluid Mechanics Questions

• Water Hammer in Pipes – Cause of pressure surge Water hammer (hammer blow) in a pipeline occurs under which operating condition?
• Flat Plate in a Stream – Orientation vs pressure/drag When a thin plate is immersed in a liquid with its plane parallel to the flow direction, the pressure force experienced is __________ that for the same plate oriented perpendicular to the flow.
• Open Channel – Most economical trapezoidal section The discharge through a trapezoidal channel is maximum (most economical section) when which geometric condition holds?
• Basic Property – Volume change with pressure The variation of the volume of a liquid with variation of pressure is defined as its what property?
• Unsteady outflow – Time to empty a hemispherical tank A hemispherical tank of radius R has a small orifice of cross-sectional area a at its bottom and is initially full of liquid. Assuming a constant coefficient of discharge Cd and neglecting viscous head losses other than at the orifice, what is the time required to empty the tank completely?
• Pressure scales – Relation between absolute, gauge, and atmospheric Absolute pressure is related to gauge pressure and atmospheric pressure by which expression?
• Flow visualization – Definition of streamline The imaginary curve drawn in a flowing fluid such that the tangent at any point gives the instantaneous direction of motion at that point is called a what?
• Units – Kinematic viscosity in SI What is the SI unit of kinematic viscosity (nu)?
• Hydrostatics – Pressure variation with depth At any point within a static liquid, the intensity of pressure varies how with depth measured below the free surface?
• Buoyancy – line of action and center of buoyancy The line of action of the buoyant force (upthrust) on a submerged or floating body passes through the centre of gravity of the displaced liquid volume, i.e., the centroid of the displaced volume. State whether this statement is correct:
• Flow dimensionality – interpretation of streamlines A flow whose streamlines form a curve in a plane (i.e., velocity components vary in two spatial directions) is best described as:
• Units – the meaning of the stoke (St) “Stoke” refers to which of the following physical quantities and unit systems?
• Weirs – definition of a narrow-crested weir A sharp-edged weir is called a narrow-crested weir if the width of its crest is __________ half the head of water above the crest (measured upstream):
• Pressure measurement – meaning of vacuum pressure Is it correct to say that “vacuum pressure” is always the negative of the gauge pressure (i.e., vacuum pressure = − gauge pressure when pressure is below atmospheric)?
• Rotating liquid in a vertical-axis cylinder – depth of paraboloid A cylindrical vessel of radius r is rotated steadily at angular speed ω about its vertical axis. The free surface becomes a paraboloid. The depth difference between the rim and the vertex (parabola depth) is:
• Discharge coefficients – relation among Cv, Cc, and Cd For a sharp-edged orifice/mouthpiece, the coefficient of discharge (Cd) is __________ the coefficient of velocity (Cv):
• Flow regimes – velocity and turbulence “Turbulent flow takes place at high velocities.” Do you agree with this general statement for internal flows in pipes?
• Dimensionless groups – force ratios in fluid flow The ratio of inertia force to viscous force in a flow is known as:
• Pressure measurement with a piezometer tube The pressure indicated by a simple piezometer tube connected to a pipe (open to atmosphere at the tube top) is:
• Open-Channel Flow Classification – Depth vs Critical Depth If the actual flow depth in an open channel is greater than the critical depth, the regime is called subcritical (also termed tranquil) flow. This state is gravity-dominated with Froude number less than 1.