27 real Fluid Mechanics & Transport questions from the Chemical Core bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Reynolds number?
Junior
A.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
B.manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
C.energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
D.laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
2. Which term means: "dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000"?
A.Reynolds number — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
B.Reynolds number — energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
C.Reynolds number — manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
D.Reynolds number — dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
A.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
B.dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
C.energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
D.laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
5. Which term means: "energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline"?
A.Bernoulli equation — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
B.Bernoulli equation — laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
C.Bernoulli equation — energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
D.Bernoulli equation — orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
A.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
B.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
C.centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
D.fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
8. Which term means: "fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air"?
A.Newtonian fluid — vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
B.Newtonian fluid — fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
C.Newtonian fluid — energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
D.Newtonian fluid — dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
A.laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
B.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
C.centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
D.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
11. Which term means: "laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter"?
A.Hagen-Poiseuille equation — energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
B.Hagen-Poiseuille equation — laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
C.Hagen-Poiseuille equation — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
D.Hagen-Poiseuille equation — fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
A.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
B.fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
C.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
D.dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
14. Which term means: "dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation"?
A.Fanning friction factor — centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
B.Fanning friction factor — manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
C.Fanning friction factor — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
D.Fanning friction factor — vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
A.fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
B.centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
C.manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
D.orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
17. Which term means: "orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98"?
A.Orifice meter vs venturi — fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
B.Orifice meter vs venturi — manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
C.Orifice meter vs venturi — energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
D.Orifice meter vs venturi — orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
A.dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
B.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
C.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
D.manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
20. Which term means: "manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve"?
A.Pump characteristic curve — manufacturer plot of head, efficiency and power against flow rate; the operating point is where it intersects the system resistance curve
B.Pump characteristic curve — fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
C.Pump characteristic curve — centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
D.Pump characteristic curve — dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
A.laminar pipe-flow relation in which pressure drop is proportional to viscosity, length and flow rate and inversely to the fourth power of diameter
B.energy balance for steady inviscid incompressible flow stating that pressure head, velocity head and elevation head sum to a constant along a streamline
C.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
D.vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
23. Which term means: "vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required"?
A.Cavitation — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
B.Cavitation — dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
C.Cavitation — vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
D.Cavitation — orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
A.fluid whose shear stress is directly proportional to shear rate, so viscosity stays constant at a fixed temperature, as for water and air
B.dimensionless ratio of inertial to viscous forces (ρvD/μ); pipe flow is laminar below about 2100 and fully turbulent above roughly 4000
C.centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
D.orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
26. Which term means: "centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings"?
A.Affinity laws — vapour bubbles forming and collapsing when suction pressure falls below liquid vapour pressure, pitting the impeller; prevented by keeping NPSH available above NPSH required
B.Affinity laws — orifice plate is cheap but wastes most of its differential as permanent loss (coefficient about 0.61); venturi recovers pressure with a coefficient near 0.98
C.Affinity laws — centrifugal pump flow varies with speed, head with speed squared and power with speed cubed, which is the basis of VFD energy savings
D.Affinity laws — dimensionless wall-shear parameter equal to 16/Re in laminar flow and one quarter of the Darcy factor, used in the ΔP = 4f(L/D)(ρv²/2) equation
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