The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its (A) Viscosity (B) Specific volume (C) Velocity (D) None of these

The flow of gas along a pipe in the direction of decreasing pressure
causes decrease in its
(A) Viscosity
(B) Specific volume
(C) Velocity
(D) None of these
by

1 Answer

Answer :

(B) Specific volume
by

Related questions

Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict pressure drop

Description : Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Data insufficient to predict pressure drop

Last Answer : (A) Increase

Pressure gradient in the pipe flow is influenced by the (A) Diameter of pipe (B) Velocity of the fluid (C) Density & viscosity of the fluid (D) All (A), (B) and (C)

Description : Pressure gradient in the pipe flow is influenced by the (A) Diameter of pipe (B) Velocity of the fluid (C) Density & viscosity of the fluid (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Pick out the wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads (D) Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

Description : Pick out the wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres ( ... factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number

Last Answer : (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads

For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) (A) μ (B) 1/μ (C) √μ (D) 1/√μ

Description : For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) (A) μ (B) 1/μ (C) √μ (D) 1/√μ

Last Answer : (B) 1/μ

Critical velocity in a pipe flow (A) Increases as fluid viscosity increases (B) Increases as pipe diameter increases (C) Independent of fluid density (D) None of these

Description : Critical velocity in a pipe flow (A) Increases as fluid viscosity increases (B) Increases as pipe diameter increases (C) Independent of fluid density (D) None of these

Last Answer : (B) Increases as pipe diameter increases

In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will (A) Decrease gradually (B) Increase gradually (C) Increase rapidly (D) Remain constant

Description : In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will (A) Decrease gradually (B) Increase gradually (C) Increase rapidly (D) Remain constant

Last Answer : (B) Increase gradually

he pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe at the same flow rate/average velocity, then the pressure drop in this case will be (A) Δp (B) 2Δp (C) Δp 2 (D) Δp/2

Description : he pressure drop per unit length of pipe incurred by a fluid 'X' flowing through pipe is Δp. If another fluid 'Y' having both the specific gravity & density just double of that of fluid 'X', flows through the same pipe ... then the pressure drop in this case will be (A) Δp (B) 2Δp (C) Δp 2 (D) Δp/2

Last Answer : (B) 2Δp

A streamline is defined as the line (A) Parallel to central axis flow (B) Parallel to outer surface of pipe (C) Of equal velocity in a flow (D) Along which the pressure drop is uniform

Description : A streamline is defined as the line (A) Parallel to central axis flow (B) Parallel to outer surface of pipe (C) Of equal velocity in a flow (D) Along which the pressure drop is uniform

Last Answer : Answer: Option C

Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the centre of the pipe. 4. Hydraulic gradient varies as the square of the mean velocity of flow. Which of these statements are correct? (a) 1, 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only

Description : Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the ... 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only

Last Answer : (b) 1 & 3 only

An example of unsteady non uniform flow is the flow of liquid under pressure through a (A) Tapering pipe at constant flow rate (B) Tapering pipe at either decreasing or increasing flow rate (C) Long pipeline of constant diameter (D) None of these

Description : An example of unsteady non uniform flow is the flow of liquid under pressure through a (A) Tapering pipe at constant flow rate (B) Tapering pipe at either decreasing or increasing flow rate (C) Long pipeline of constant diameter (D) None of these

Last Answer : (B) Tapering pipe at either decreasing or increasing flow rate

The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v w = Specific weight of the flowing liquid) (A) 4 (B) 8 (C) 16 (D) 32

Description : The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v w = Specific weight of the flowing liquid) (A) 4 (B) 8 (C) 16 (D) 32

Last Answer : Answer: Option D

A gas (density = 1.5 kg/m3 , viscosity = 2 × 10 ‒5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 × 10 ‒5kg/m.s flowing at 3 m/s will be (A) 8400 Pa/m (B) 12600 Pa/m (C) 18900 Pa/m (D) 16800 Pa/m

Description : A gas (density = 1.5 kg/m3 , viscosity = 2 10 -5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The ... flowing at 3 m/s will be (A) 8400 Pa/m (B) 12600 Pa/m (C) 18900 Pa/m (D) 16800 Pa/m

Last Answer : (B) 12600 Pa/m

Discharge in laminar flow through a pipe varies (A) As the square of the radius (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the diameter

Description : Discharge in laminar flow through a pipe varies (A) As the square of the radius (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the diameter

Last Answer : (A) As the square of the radius

In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder (C) Velocity profile varies hyperbolically and the shear stress remains constant over the cross-section (D) Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Description : In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a ... occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

Last Answer : (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder

Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation (B) Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities (C) Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise(D) Large scale cavitation cannot damage pipeline, restrict fluid flow anddamage steam turbine blades

Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades

A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by (A) Decreasing the size of the inlet pipe (B) Increasing the size of the inlet pipe (C) Lowering the pump position (D) Both (B) and (C)

Description : A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by (A) Decreasing the size of the inlet pipe (B) Increasing the size of the inlet pipe (C) Lowering the pump position (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is (A) The velocity of sound (B) Dependent on its cross-sectional area (C) Dependent on fluid viscosity (D) Dependent on fluid density

Description : In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is (A) The velocity of sound (B) Dependent on its cross-sectional area (C) Dependent on fluid viscosity (D) Dependent on fluid density

Last Answer : (A) The velocity of sound

Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop

Description : Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the ... (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop

Last Answer : (B) Decrease

Unsteady uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Description : Unsteady uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Last Answer : (B) Long pipe at decreasing rate

Steady uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at constant rate (D) None of these

Description : Steady uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at constant rate (D) None of these

Last Answer : (A) Long pipe at constant rate

Steady non-uniform flow is exemplified by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Description : Steady non-uniform flow is exemplified by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Last Answer : (D) Expanding tube at constant rate

Unsteady non-uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Description : Unsteady non-uniform flow is represented by flow through a/an (A) Long pipe at constant rate (B) Long pipe at decreasing rate (C) Expanding tube at increasing rate (D) Expanding tube at constant rate

Last Answer : (C) Expanding tube at increasing rate

Select the correct practical example of steady non-uniform flow. (A) Motion of water around a ship in a lake (B) Motion of river around bridge piers (C) Steadily decreasing flow through a reducing section (D) Steadily increasing flow through a pipe

Description : Select the correct practical example of steady non-uniform flow. (A) Motion of water around a ship in a lake (B) Motion of river around bridge piers (C) Steadily decreasing flow through a reducing section (D) Steadily increasing flow through a pipe

Last Answer : (C) Steadily decreasing flow through a reducing section

Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Be quadrupled

Description : Assuming flow to be laminar, if the diameter of the pipe is halved, then the pressure drop will (A) Increase (B) Decrease (C) Remain same (D) Be quadrupled

Last Answer : (A) Increase

The continuity equation in ideal fluid flow states that (A) Net rate of inflow into any small volume must be zero (B) Energy is not constant along a streamline (C) Energy is constant along a streamline (D) There exists a velocity potential

Description : The continuity equation in ideal fluid flow states that (A) Net rate of inflow into any small volume must be zero (B) Energy is not constant along a streamline (C) Energy is constant along a streamline (D) There exists a velocity potential

Last Answer : (A) Net rate of inflow into any small volume must be zero

In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the (A) Square root of the velocity (B) Square of the viscosity (C) Filtration time only (D) Washing time only

Description : In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the (A) Square root of the velocity (B) Square of the viscosity (C) Filtration time only (D) Washing time only

Last Answer : (A) Square root of the velocity

Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

Description : Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent ... of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid

Last Answer : (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity

Friction factor for fluid flow in pipe does not depend upon the (A) Pipe length (B) Pipe roughness (C) Fluid density & viscosity (D) Mass flow rate of fluid

Description : Friction factor for fluid flow in pipe does not depend upon the (A) Pipe length (B) Pipe roughness (C) Fluid density & viscosity (D) Mass flow rate of fluid

Last Answer : A) Pipe length

Hydraulic intensifier is used for increasing the (A) Rate of velocity of liquid supply (B) Rate of flow through delivery pipeline of a pump (C) Intensity of pressure of the liquid (D) Momentum rate through delivery pipe

Description : Hydraulic intensifier is used for increasing the (A) Rate of velocity of liquid supply (B) Rate of flow through delivery pipeline of a pump (C) Intensity of pressure of the liquid (D) Momentum rate through delivery pipe

Last Answer : (C) Intensity of pressure of the liquid

The Prandtl Pitot tube measures the (A) Velocity at a point in the flow (B) Pressure at a point (C) Average flow velocity (D) Pressure difference in pipe flow

Description : The Prandtl Pitot tube measures the (A) Velocity at a point in the flow (B) Pressure at a point (C) Average flow velocity (D) Pressure difference in pipe flow

Last Answer : (A) Velocity at a point in the flow

The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. (A) Newtonian (B) Pseudo-plastic (C) Dilatent (D) Bingham plastic

Description : The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. (A) Newtonian (B) Pseudo-plastic (C) Dilatent (D) Bingham plastic

Last Answer : (B) Pseudo-plastic

The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. (A) Newtonian (B) Dilatant (C) Pseudo-plastic (D) Non-Newtonian

Description : The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. (A) Newtonian (B) Dilatant (C) Pseudo-plastic (D) Non-Newtonian

Last Answer : (A) Newtonian

The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of __________ fluid. (A) Dilatent (B) Pseudo-plastic (C) Bingham plastic (D) Newtonian

Description : The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of __________ fluid. (A) Dilatent (B) Pseudo-plastic (C) Bingham plastic (D) Newtonian

Last Answer : (A) Dilatent

For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the (A) Square of the radial distance (B) Radial distance linearly (C) Inverse of the radial distance(D) Elevation along vertical direction

Description : For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the (A) Square of the radial distance (B) Radial distance linearly (C) Inverse of the radial distance (D) Elevation along vertical direction

Last Answer : (A) Square of the radial distance

A flow through a long pipe at decreasing rate is called __________ uniform flow. (A) Steady (B) Unsteady (C) Both A and B (D) None of these

Description : A flow through a long pipe at decreasing rate is called __________ uniform flow. (A) Steady (B) Unsteady (C) Both A and B (D) None of these

Last Answer : Answer: Option B

Bulk modulus of a fluid is the ratio of (A) Shear stress to shear strain (B) Increase in volume to the viscosity of fluid (C) Increase in pressure to the volumetric strain (D) Critical velocity to the viscosity of fluid

Description : Bulk modulus of a fluid is the ratio of (A) Shear stress to shear strain (B) Increase in volume to the viscosity of fluid (C) Increase in pressure to the volumetric strain (D) Critical velocity to the viscosity of fluid

Last Answer : Answer: Option C

The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x0.5 while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge) (A) x1.5 (B) x0.8 (C) x-1.5 (D) x-0.8

Description : The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x0.5 while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge) (A) x1.5 (B) x0.8 (C) x-1.5 (D) x-0.8

Last Answer : (B) x0.8

The terminal velocity of a small sphere settling in a viscous fluid varies as the (A) First power of its diameter (B) Inverse of the fluid viscosity (C) Inverse square of the diameter (D) Square of the difference in specific weights of solid & fluid

Description : The terminal velocity of a small sphere settling in a viscous fluid varies as the (A) First power of its diameter (B) Inverse of the fluid viscosity (C) Inverse square of the diameter (D) Square of the difference in specific weights of solid & fluid

Last Answer : (B) Inverse of the fluid viscosity

Which of the following statement is wrong? (A) A flow whose streamline is represented by a curve is called two dimensional flow. (B) The total energy of a liquid particle is the sum of potential energy, kinetic energy and pressure energy. (C) The length of divergent portion in a Venturimeter is equal to the convergent portion. (D) A pitot tube is used to measure the velocity of flow at the required point in a pipe.

Description : Which of the following statement is wrong? (A) A flow whose streamline is represented by a curve is called two dimensional flow. (B) The total energy of a liquid particle is the sum of potential energy, ... (D) A pitot tube is used to measure the velocity of flow at the required point in a pipe.

Last Answer : Answer: Option C

A pitot tube is used to measure the (A) Velocity of flow at the required point in a pipe (B) Pressure difference between two points in a pipe (C) Total pressure of liquid flowing in a pipe (D) Discharge through a pipe

Description : A pitot tube is used to measure the (A) Velocity of flow at the required point in a pipe (B) Pressure difference between two points in a pipe (C) Total pressure of liquid flowing in a pipe (D) Discharge through a pipe

Last Answer : Answer: Option A

When a liquid moves through a pipe having a varying diameter, the pressure against the inside walls of the pipe will be: w) the same throughout x) lowest where the diameter is smallest y) lowest where the diameter is largest z) lowest where the velocity of flow is lowest

Description : When a liquid moves through a pipe having a varying diameter, the pressure against the inside walls of the pipe will be: w) the same throughout x) lowest where the diameter is smallest y) lowest where the diameter is largest z) lowest where the velocity of flow is lowest 

Last Answer : ANSWER: X -- LOWEST WHERE THE DIAMETER IS SMALLEST

Minimum fluidisation velocity for a specific system depends upon the (A) Particle size (B) Fluid viscosity (C) Density of both the particle & the fluid (D) All (A), (B) and (C)

Description : Minimum fluidisation velocity for a specific system depends upon the (A) Particle size (B) Fluid viscosity (C) Density of both the particle & the fluid (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Which of the following is a dimensionless parameter? (A) Angular velocity (B) Specific weight (C) Kinematic viscosity (D) None of these

Description : Which of the following is a dimensionless parameter? (A) Angular velocity (B) Specific weight (C) Kinematic viscosity (D) None of these

Last Answer : (D) None of these

A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20microns settling in the same oil will have a settling velocity (A) Same as that of A (B) One fourth as that of A (C) Twice as that of A (D) Four times as that of A

Description : A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20microns settling in the same oil will have a settling velocity (A) ... ) One fourth as that of A (C) Twice as that of A (D) Four times as that of A

Last Answer : (B) One fourth as that of A

In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will (A) Increase (B) Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Description : In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation ... Decrease (C) Remain unchanged (D) Either increase or decrease; depends on the coolant flow rate

Last Answer : (C) Remain unchanged

How does the decreasing the gas volume affect the pressure of a gas?

Description : How does the decreasing the gas volume affect the pressure of a gas?

Last Answer : The pressure increase.

For gas absorption, low viscosity solvents are preferred, because of their (A) Better flow characteristics (B) Low pumping pressure drop (C) Rapid absorption rates(D) All (A), (B) and (C)

Description : For gas absorption, low viscosity solvents are preferred, because of their (A) Better flow characteristics (B) Low pumping pressure drop (C) Rapid absorption rates (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Pick out the wrong statement. (A) Momentum transfer in laminar flow results from velocity gradient (B) A fluid in equilibrium is not free from shear stress (C) The viscosity of a non-Newtonian fluid is a function of temperature only (D) Both (B) and (C)

Description : Pick out the wrong statement. (A) Momentum transfer in laminar flow results from velocity gradient (B) A fluid in equilibrium is not free from shear stress (C) The viscosity of a non-Newtonian fluid is a function of temperature only (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Momentum transfer in laminar flow of fluids results due to the (A) Viscosity (B) Density (C) Velocity gradient (D) None of these

Description : Momentum transfer in laminar flow of fluids results due to the (A) Viscosity (B) Density (C) Velocity gradient (D) None of these

Last Answer : (C) Velocity gradient