Given laminar fully developed flow in an elliptical duct of semiaxes a and b. Show that, for a given pressure gradient, the flow rate per unit area is a maximum when a=b.

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Given laminar fully developed flow in an elliptical duct of semiaxes a and b. Show that, for a given pressure gradient, the flow rate per unit area is a maximum when a=b.

 

1. Answer the following questions:
(a) What is the physical meaning of the following:
D a
Dt
where V is the velocity vector of the flow field.
(b) Let the viscous stress tensor be denoted by 7. How is the surface (vector) force f, acting by
the fluid on a surface element ds (with unit normal în ) computed? Give your answer in vector
notation and also in index notation. What is the physical meaning of tyy ?
(c) Write down the work done on a material volume of fluid by the viscous surface force in
vector notation and also in index notation.
(d) Write down the amount of conduction heat flux 'q' (a scalar) on a surface element ds (with
unit normal în ) in vector notation and also in index notation.
2. Two plates and a fixed surface sandwich two viscous fluid films as shown in the figure. The
top plate moves with a velocity of 1.5 m/s and the lower plate is free to move under the influence
of the viscous force applied to it. The contact areas for the lower surface of the upper plate is the
same as the upper surface of the lower plate as well as the lower surface of lower plate and that
of the fixed surface. The density of both fluid is 850 kg/m3. hı=2 mm, hz=1 mm, µi=0.2 Pas.
u2=0.5 Pas.
(a) After steady state conditions have been reached, what is the velocity of the lower plate?
(b) What is the force per unit area imposed on the upper plate to maintain its velocity?
Upper plate
Viscous fluid 1
h1
Lower plate
Viscous fluid 2
h2
Fixed surface.
3. Unsteady flow between two infinite plates. The upper plate (y-h) is fixed; at time t=0, the
lower plate (y=0) begins to move at uniform velocity Uo. Starting from governing equations for
parallel flow and list all assumptions, solve the unsteady PDE by separation of variables.
4. Given laminar fully developed flow in an elliptical duct of şemiaxes a and b. Show that, for a
given pressure gradient, the flow rate per unit area is a maximum when a=b.
Transcribed Image Text:1. Answer the following questions: (a) What is the physical meaning of the following: D a Dt where V is the velocity vector of the flow field. (b) Let the viscous stress tensor be denoted by 7. How is the surface (vector) force f, acting by the fluid on a surface element ds (with unit normal în ) computed? Give your answer in vector notation and also in index notation. What is the physical meaning of tyy ? (c) Write down the work done on a material volume of fluid by the viscous surface force in vector notation and also in index notation. (d) Write down the amount of conduction heat flux 'q' (a scalar) on a surface element ds (with unit normal în ) in vector notation and also in index notation. 2. Two plates and a fixed surface sandwich two viscous fluid films as shown in the figure. The top plate moves with a velocity of 1.5 m/s and the lower plate is free to move under the influence of the viscous force applied to it. The contact areas for the lower surface of the upper plate is the same as the upper surface of the lower plate as well as the lower surface of lower plate and that of the fixed surface. The density of both fluid is 850 kg/m3. hı=2 mm, hz=1 mm, µi=0.2 Pas. u2=0.5 Pas. (a) After steady state conditions have been reached, what is the velocity of the lower plate? (b) What is the force per unit area imposed on the upper plate to maintain its velocity? Upper plate Viscous fluid 1 h1 Lower plate Viscous fluid 2 h2 Fixed surface. 3. Unsteady flow between two infinite plates. The upper plate (y-h) is fixed; at time t=0, the lower plate (y=0) begins to move at uniform velocity Uo. Starting from governing equations for parallel flow and list all assumptions, solve the unsteady PDE by separation of variables. 4. Given laminar fully developed flow in an elliptical duct of şemiaxes a and b. Show that, for a given pressure gradient, the flow rate per unit area is a maximum when a=b.
1. Answer the following questions:
(a) What is the physical meaning of the following:
D a
Dt
where V is the velocity vector of the flow field.
(b) Let the viscous stress tensor be denoted by 7. How is the surface (vector) force f, acting by
the fluid on a surface element ds (with unit normal în ) computed? Give your answer in vector
notation and also in index notation. What is the physical meaning of tyy ?
(c) Write down the work done on a material volume of fluid by the viscous surface force in
vector notation and also in index notation.
(d) Write down the amount of conduction heat flux 'q' (a scalar) on a surface element ds (with
unit normal în ) in vector notation and also in index notation.
2. Two plates and a fixed surface sandwich two viscous fluid films as shown in the figure. The
top plate moves with a velocity of 1.5 m/s and the lower plate is free to move under the influence
of the viscous force applied to it. The contact areas for the lower surface of the upper plate is the
same as the upper surface of the lower plate as well as the lower surface of lower plate and that
of the fixed surface. The density of both fluid is 850 kg/m3. hı=2 mm, hz=1 mm, µi=0.2 Pas.
u2=0.5 Pas.
(a) After steady state conditions have been reached, what is the velocity of the lower plate?
(b) What is the force per unit area imposed on the upper plate to maintain its velocity?
Upper plate
Viscous fluid 1
h1
Lower plate
Viscous fluid 2
h2
Fixed surface.
3. Unsteady flow between two infinite plates. The upper plate (y-h) is fixed; at time t=0, the
lower plate (y=0) begins to move at uniform velocity Uo. Starting from governing equations for
parallel flow and list all assumptions, solve the unsteady PDE by separation of variables.
4. Given laminar fully developed flow in an elliptical duct of şemiaxes a and b. Show that, for a
given pressure gradient, the flow rate per unit area is a maximum when a=b.
Transcribed Image Text:1. Answer the following questions: (a) What is the physical meaning of the following: D a Dt where V is the velocity vector of the flow field. (b) Let the viscous stress tensor be denoted by 7. How is the surface (vector) force f, acting by the fluid on a surface element ds (with unit normal în ) computed? Give your answer in vector notation and also in index notation. What is the physical meaning of tyy ? (c) Write down the work done on a material volume of fluid by the viscous surface force in vector notation and also in index notation. (d) Write down the amount of conduction heat flux 'q' (a scalar) on a surface element ds (with unit normal în ) in vector notation and also in index notation. 2. Two plates and a fixed surface sandwich two viscous fluid films as shown in the figure. The top plate moves with a velocity of 1.5 m/s and the lower plate is free to move under the influence of the viscous force applied to it. The contact areas for the lower surface of the upper plate is the same as the upper surface of the lower plate as well as the lower surface of lower plate and that of the fixed surface. The density of both fluid is 850 kg/m3. hı=2 mm, hz=1 mm, µi=0.2 Pas. u2=0.5 Pas. (a) After steady state conditions have been reached, what is the velocity of the lower plate? (b) What is the force per unit area imposed on the upper plate to maintain its velocity? Upper plate Viscous fluid 1 h1 Lower plate Viscous fluid 2 h2 Fixed surface. 3. Unsteady flow between two infinite plates. The upper plate (y-h) is fixed; at time t=0, the lower plate (y=0) begins to move at uniform velocity Uo. Starting from governing equations for parallel flow and list all assumptions, solve the unsteady PDE by separation of variables. 4. Given laminar fully developed flow in an elliptical duct of şemiaxes a and b. Show that, for a given pressure gradient, the flow rate per unit area is a maximum when a=b.
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