99 + Interview Questions in Fluid Mechanics Page 2 InterviewSolution

51.	Consider a laminar flow at zero incidence over a flat plate.The shear stress at the wall is denoted by τw. The axial position x1 andx2 on the plate are measured from the leading edge in the direction of flow.If x2>x1,then
Answer» Consider a laminar flow at zero incidence over a flat plate.The shear stress at the wall is denoted by $τ_{w}$ . The axial position $x_{1}$ and $x_{2}$ on the plate are measured from the leading edge in the direction of flow.If $x_{2} > x_{1}$ ,then

Discussion

52.	The relation that must hold for the flow to be irrotational is
Answer» The relation that must hold for the flow to be irrotational is

Discussion

53.	The overall drag coefficient of an aircraft of weight W and wing area S is given by CD=a+bC2LWhere 'a' and 'b' are constants. The maximum drag in horizontal flight will be
Answer» The overall drag coefficient of an aircraft of weight W and wing area S is given by $C_{D} = a + b C_{L}^{2}$ Where 'a' and 'b' are constants. The maximum drag in horizontal flight will be

Discussion

54.	An aluminium alloy (density 2600 kg/m3) casting is to be produced. A cylindrical hole of 100 mm diameter and 100 mm length is made in the casting using sand core (density 1600 kg/m3) . The net buoyancy force (in Newton) acting on the core is_____7.7
Answer» An aluminium alloy (density 2600 kg/ $m^{3}$ ) casting is to be produced. A cylindrical hole of 100 mm diameter and 100 mm length is made in the casting using sand core (density 1600 kg/ $m^{3}$ ) . The net buoyancy force (in Newton) acting on the core is_____ 7.7

Discussion

55.	Water flows through pipe with a velocity given by→V=(4t+x+y)^j m/s,where ^j is the unit vector in the y direction, t(>0) is in second, and x and y are in meters. The magnitude of total acceleration at the point (x,y)= (1,1) at t=2s is_____ m/s2 3
Answer» Water flows through pipe with a velocity given by $\to V = (\frac{4}{t} + x + y)^j m / s$ , where $^j$ is the unit vector in the y direction, t(>0) is in second, and x and y are in meters. The magnitude of total acceleration at the point (x,y)= (1,1) at t=2s is_____ $m / s^{2}$ 3

Discussion

56.	Euler number or pressure coefficient may be represented as (notations have their usual meanings)
Answer» Euler number or pressure coefficient may be represented as (notations have their usual meanings)

Discussion

57.	Three parallel pipes connected at the two ends have flow-rates Q1,Q2 and Q3 respectively and the corresponding frictional head losses are hL1,hL2, and hL3 respectively. The correct expressions for total flow rate (Q) and frictional head loss across the two ends (hL) are
Answer» Three parallel pipes connected at the two ends have flow-rates $Q_{1}, Q_{2} a n d Q_{3}$ respectively and the corresponding frictional head losses are $h_{L 1}, h_{L 2}, a n d h_{L 3}$ respectively. The correct expressions for total flow rate (Q) and frictional head loss across the two ends $(h_{L})$ are

Discussion

58.	Air (ρ=1.2kg/m3 and kinematic viscosity, v=2×10−5m2/s ) with a velocity of 2 m/s flows over the top surface of a flat plate of length 2.5 m. If the average value of friction coefficient is Cf=1.328√Rex, the total drag force (in N) per unit width of the plate is_________0.0159
Answer» Air $(ρ = 1.2 k g / m^{3}$ and kinematic viscosity, $v = 2 \times 10^{- 5} m^{2} / s)$ with a velocity of 2 m/s flows over the top surface of a flat plate of length 2.5 m. If the average value of friction coefficient is $C_{f} = \frac{1.328}{{\sqrt{R e}}_{x}}$ , the total drag force (in N) per unit width of the plate is_________ 0.0159

Discussion

59.	In a laminar boundary layer, the velocity distribution can be assumed to be given, in usual notations, asuv=yδWhich one of the following is the correct experession for the displacement thickness (δ∗) for this boundary layer?
Answer» In a laminar boundary layer, the velocity distribution can be assumed to be given, in usual notations, as $\frac{u}{v} = \frac{y}{δ}$ Which one of the following is the correct experession for the displacement thickness $(δ^{*})$ for this boundary layer?

Discussion

60.	The friction factor (f), in terms of boundary shear stress (τ0) is given by ρ = mass density,V= mean velocity
Answer» The friction factor (f), in terms of boundary shear stress $(τ_{0})$ is given by $ρ = m a s s d e n s i t y, V = m e a n v e l o c i t y$

Discussion

61.	A triangular pipe network is shown in the figureThe head loss in each pipe is given by hf =r.Q1.8 with the variables expressed in a consistent set of units. The value of r for the pipe AB is 1 and for the pipe BC is 2. If the discharge supplied at the point A (i.e., 100) is equally divided between the pipes AB and AC, the value of r (up to 2 decimal places) for the pipe AC should be0.62
Answer» A triangular pipe network is shown in the figure The head loss in each pipe is given by $h_{f} = r . Q^{1.8}$ with the variables expressed in a consistent set of units. The value of r for the pipe AB is 1 and for the pipe BC is 2. If the discharge supplied at the point A (i.e., 100) is equally divided between the pipes AB and AC, the value of r (up to 2 decimal places) for the pipe AC should be 0.62

61.

A triangular pipe network is shown in the figureThe head loss in each pipe is given by hf =r.Q1.8 with the variables expressed in a consistent set of units. The value of r for the pipe AB is 1 and for the pipe BC is 2. If the discharge supplied at the point A (i.e., 100) is equally divided between the pipes AB and AC, the value of r (up to 2 decimal places) for the pipe AC should be0.62

Answer»

A triangular pipe network is shown in the figure

The head loss in each pipe is given by $h_{f} = r . Q^{1.8}$ with the variables expressed in a consistent set of units. The value of r for the pipe AB is 1 and for the pipe BC is 2. If the discharge supplied at the point A (i.e., 100) is equally divided between the pipes AB and AC, the value of r (up to 2 decimal places) for the pipe AC should be

0.62

Discussion

62.	A right circular cylinder, open at the top, is full of water. It is rotated about the vertical axis at such a speed that half the liquid spills out. The pressure at the centre of the bottom would be
Answer» A right circular cylinder, open at the top, is full of water. It is rotated about the vertical axis at such a speed that half the liquid spills out. The pressure at the centre of the bottom would be

Discussion

63.	The flow in a channel is laminar and Reynold′s number is given by 1200 .What is the friction factor for the channel?
Answer» $T h e f l o w i n a c h a n n e l i s l a m i n a r a n d R e y n o l d^{'} s n u m b e r i s g i v e n b y 1200 . W h a t i s t h e f r i c t i o n f a c t o r f o r t h e c h a n n e l ?$

Discussion

64.	The aerodynamic drag on a sports car depends on its shape. The car has a drag coefficient of 0.1 with the windows and the roof closed. With the windows and the roof open, the drag coefficient becomes 0.8. The car travels at 44 km/h with the windows and roof closed for the same amount of power needed to overcome the aerodynamic drag, the speed of the car with the windows and roof open (round off to two decimal places), is ______km/h. (density of air and the frontal area may be assumed to be constant).22
Answer» The aerodynamic drag on a sports car depends on its shape. The car has a drag coefficient of 0.1 with the windows and the roof closed. With the windows and the roof open, the drag coefficient becomes 0.8. The car travels at 44 km/h with the windows and roof closed for the same amount of power needed to overcome the aerodynamic drag, the speed of the car with the windows and roof open (round off to two decimal places), is ______km/h. (density of air and the frontal area may be assumed to be constant). 22

Discussion

65.	A river model is constructed to a horizontal scale of 1 : 1000 and a vertical scale of 1 : 100. A model discharge of 0.1 m3/s would correspond to a discharge in the prototype, of what magnitude?
Answer» A river model is constructed to a horizontal scale of 1 : 1000 and a vertical scale of 1 : 100. A model discharge of 0.1 $m^{3}$ /s would correspond to a discharge in the prototype, of what magnitude?

Discussion

66.	Which one of the following can be a set of velocity components of a two-dimensional flow?
Answer» Which one of the following can be a set of velocity components of a two-dimensional flow?

Discussion

67.	The discharge in m3/s for laminar flow through a pipe of diameter 0.04 m having a centre line velocity of 1.5m/s is
Answer» The discharge in $m^{3} / s$ for laminar flow through a pipe of diameter 0.04 m having a centre line velocity of 1.5m/s is

Discussion

68.	What is the streamline equation passing through (1,1) for the following flow.V=3xi−3yj
Answer» What is the streamline equation passing through (1,1) for the following flow. $V = 3 x i - 3 y j$

Discussion

69.	In model similarity, if gravitational and inertial forces are the only important forces, then what is the discharge ratio?Where Lr = ratio of length dimension.
Answer» In model similarity, if gravitational and inertial forces are the only important forces, then what is the discharge ratio? Where $L_{r}$ = ratio of length dimension.

Discussion

70.	The velocity profile of a fully developed laminar flow in a straight circular pipe, as shown in the figure,given by the expressionu(r)=R24μ(∂p∂x)(1−r2R2)where ∂p∂x is a constantThe average velocity of fluid in the pipe is
Answer» The velocity profile of a fully developed laminar flow in a straight circular pipe, as shown in the figure, given by the expression $u (r) = \frac{R^{2}}{4 μ} (\frac{\partial p}{\partial x}) (1 - \frac{r^{2}}{R^{2}})$ where $\frac{\partial p}{\partial x}$ is a constant The average velocity of fluid in the pipe is

Discussion

71.	Three reservoirs A, B and C are interconnected by pipes as shown in the given figure. Water surface elevations in the reservoirs and the piezometric level at the junction D are also indicated in the figure.Flow Q1,Q2 and Q3 are related as
Answer» Three reservoirs A, B and C are interconnected by pipes as shown in the given figure. Water surface elevations in the reservoirs and the piezometric level at the junction D are also indicated in the figure. $Flow Q_{1}, Q_{2} and Q_{3} are related as$

Discussion

72.	Consider a flow through a nozzle, as shown in the figure belowThe air flow is steady, incompressible and inviscid. The density of air is 1.23 kg/m3. The pressure difference (p1−patm) is ______kPa (round off to the nearest integer).1.52
Answer» Consider a flow through a nozzle, as shown in the figure below The air flow is steady, incompressible and inviscid. The density of air is 1.23 $k g / m^{3}$ . The pressure difference $(p_{1} - p_{a t m}$ ) is ______kPa (round off to the nearest integer). 1.52

Discussion

73.	A frictionless circular piston of area 10−2m2 and mass 100 kg sinks into a cylindrical container of the same area filled with water of density 1000 kg/m3 as shown in the figure.The container has a hole of area 10−3m2 at the bottom that is open to the atmosphere. Assuming there is no leakage from the edges of the piston and considering water to be incompressible, the magnitude of the piston velocity (in m/s) at the instant shown is_______(correct to three decimal places).1.456
Answer» A frictionless circular piston of area $10^{- 2} m^{2}$ and mass 100 kg sinks into a cylindrical container of the same area filled with water of density 1000 $k g / m^{3}$ as shown in the figure. The container has a hole of area $10^{- 3} m^{2}$ at the bottom that is open to the atmosphere. Assuming there is no leakage from the edges of the piston and considering water to be incompressible, the magnitude of the piston velocity (in m/s) at the instant shown is_______(correct to three decimal places). 1.456

Discussion

74.	A channel of width 450 mm branches into two sub-channels having width 300 mm and 200 mm as shown in figure. If the volumetric flow rate (taking unit depth) of an incompressible flow through the main channel is 0.9 m3/s and the velocity in the sub-channel of width 200 mm is 3 m/s, the velocity in the sub-channel of width 300 mm is_______m/s. Assume both inlet and outlet to be at the same elevation.1
Answer» A channel of width 450 mm branches into two sub-channels having width 300 mm and 200 mm as shown in figure. If the volumetric flow rate (taking unit depth) of an incompressible flow through the main channel is $0.9 m^{3} / s$ and the velocity in the sub-channel of width 200 mm is 3 m/s, the velocity in the sub-channel of width 300 mm is_______m/s. Assume both inlet and outlet to be at the same elevation. 1

Discussion

75.	Water flows through two different pipes A and B of the same circular cross-section but at different flow rates. The length of pipe A is 1.0 m and that of pipe B is 2.0 m. The flow in both the pipes is laminar and fully developed. If the frictional head loss across the length of the pipes is same, the ratio of volume flow rates QB/QA is ________(round off to two decimal places).0.5
Answer» Water flows through two different pipes A and B of the same circular cross-section but at different flow rates. The length of pipe A is 1.0 m and that of pipe B is 2.0 m. The flow in both the pipes is laminar and fully developed. If the frictional head loss across the length of the pipes is same, the ratio of volume flow rates $Q_{B} / Q_{A}$ is ________(round off to two decimal places). 0.5

Discussion

76.	The unit of dynamic viscosity of a fluid is
Answer» The unit of dynamic viscosity of a fluid is

Discussion

77.	A pipe of 0.7 m diameter has a length of 6 km and connects two reservoirs A and B. The water level in reservoir A is at an elevation 30 m above the water level in reservoir B. Halfway along the pipe line, there is a branch through which water can be supplied to a third reservoir C. The friction factor of the pipe is 0.024. the quantity of water discharged into reservoir C is 0.15 m3/s. Considering the acceleration due to gravity as 9.81 m/s2 and neglecting minor losses, the discharge (in m3/s) into the reservoir B is0.572
Answer» A pipe of 0.7 m diameter has a length of 6 km and connects two reservoirs A and B. The water level in reservoir A is at an elevation 30 m above the water level in reservoir B. Halfway along the pipe line, there is a branch through which water can be supplied to a third reservoir C. The friction factor of the pipe is 0.024. the quantity of water discharged into reservoir C is 0.15 m $^{3}$ /s. Considering the acceleration due to gravity as 9.81 m/s $^{2}$ and neglecting minor losses, the discharge (in m $^{3}$ /s) into the reservoir B is 0.572

77.

A pipe of 0.7 m diameter has a length of 6 km and connects two reservoirs A and B. The water level in reservoir A is at an elevation 30 m above the water level in reservoir B. Halfway along the pipe line, there is a branch through which water can be supplied to a third reservoir C. The friction factor of the pipe is 0.024. the quantity of water discharged into reservoir C is 0.15 m3/s. Considering the acceleration due to gravity as 9.81 m/s2 and neglecting minor losses, the discharge (in m3/s) into the reservoir B is0.572

Answer»

A pipe of 0.7 m diameter has a length of 6 km and connects two reservoirs A and B. The water level in reservoir A is at an elevation 30 m above the water level in reservoir B. Halfway along the pipe line, there is a branch through which water can be supplied to a third reservoir C. The friction factor of the pipe is 0.024. the quantity of water discharged into reservoir C is 0.15 m $^{3}$ /s. Considering the acceleration due to gravity as 9.81 m/s $^{2}$ and neglecting minor losses, the discharge (in m $^{3}$ /s) into the reservoir B is

0.572

Discussion

78.	A straight 100 m long raw water gravity main is to carry water from an intake structure to the jack well of a water treatment plant. The required flow through this water main is 0.21 m3. Allowable velocity through the main is 0.75 m/s. Assume f = 0.01, g = 9.81 m/s2. The minimum gradient (in cm/100 m length) to be given to this gravity main so that the required amount of water flows without any difficulty is 4.8
Answer» A straight 100 m long raw water gravity main is to carry water from an intake structure to the jack well of a water treatment plant. The required flow through this water main is 0.21 m $^{3}$ . Allowable velocity through the main is 0.75 m/s. Assume f = 0.01, g = 9.81 m/s $^{2}$ . The minimum gradient (in cm/100 m length) to be given to this gravity main so that the required amount of water flows without any difficulty is 4.8

Discussion

79.	A cylindrical body of cross-sectional area A, height H and density ρs′ is immersed to a depth h in a liquid of density ρ, and tied to the bottom with a string. The tension in the string is
Answer» A cylindrical body of cross-sectional area A, height H and density $ρ_{s^{'}}$ is immersed to a depth h in a liquid of density $ρ$ , and tied to the bottom with a string. The tension in the string is

Discussion

80.	A plane flow has velocity components u=xT1, v=−yT2 and w=0 along x, y and z directions respectively, where T1(≠0) and T2(≠0) are constants having the dimension of time. The given flow is incompressible if
Answer» A plane flow has velocity components $u = \frac{x}{T_{1}}, v = \frac{- y}{T_{2}} a n d w = 0$ along x, y and z directions respectively, where $T_{1} (\neq 0) a n d T_{2} (\neq 0)$ are constants having the dimension of time. The given flow is incompressible if

Discussion

81.	X-component of velocity in two dimensional incompressible flow is given byu=2y2+6xy. If the Y-component of velocity v is zero at y =0, the expression for Y-component of velocity is given by
Answer» X-component of velocity in two dimensional incompressible flow is given by $u = 2 y^{2} + 6 x y$ . If the Y-component of velocity v is zero at y =0, the expression for Y-component of velocity is given by

Discussion

82.	If the capillary rise of water in a 1 mm diameter tube is 3 cm, the height of capillary rise of water in a 0.2 mm diameter tube in cm will be -
Answer» If the capillary rise of water in a 1 mm diameter tube is 3 cm, the height of capillary rise of water in a 0.2 mm diameter tube in cm will be -

Discussion

83.	A cube of side 100 mm is placed at the bottom of an empty container on one of its faces. The density of the material of the cube is 800 kg/m3 . Liquid of density 1000kg/m3 is now poured into the container. The minimum height to which the liquid needs to be poured into the container for the cube to just lift up is______mm.80
Answer» A cube of side 100 mm is placed at the bottom of an empty container on one of its faces. The density of the material of the cube is 800 kg/ $m^{3}$ . Liquid of density 1000kg/ $m^{3}$ is now poured into the container. The minimum height to which the liquid needs to be poured into the container for the cube to just lift up is______mm. 80

Discussion

84.	A symmetrical right-circular cone of wood floats in fresh water with axis vertical and the apex down. The axial height of the cone is 1 unit. The submerged portion has a height h, measured upwards from the apex. What would be the height of the centre of buoyancy from the apex?
Answer» A symmetrical right-circular cone of wood floats in fresh water with axis vertical and the apex down. The axial height of the cone is 1 unit. The submerged portion has a height h, measured upwards from the apex. What would be the height of the centre of buoyancy from the apex?

Discussion

85.	An equilateral triangular plate is immersed in water as shown in the figure below. The centre of pressure below the water surface is at depth of
Answer» An equilateral triangular plate is immersed in water as shown in the figure below. The centre of pressure below the water surface is at depth of

Discussion

86.	What should be the angle of divergence in a venturimeter to avoid the flow separation ?
Answer» What should be the angle of divergence in a venturimeter to avoid the flow separation ?

Discussion

87.	The viscous laminar flow of air over a flat plate results in the formation of a boundary layer. The boundary layer thickness at the end of the plate of length L is δL. When the plate length is increased to twice of its original length, the percentage change in laminar boundary layer thickness at the end of the plate (with respect to δL) is_____(correct to two decimal places).41.42
Answer» The viscous laminar flow of air over a flat plate results in the formation of a boundary layer. The boundary layer thickness at the end of the plate of length L is $δ_{L}$ . When the plate length is increased to twice of its original length, the percentage change in laminar boundary layer thickness at the end of the plate (with respect to $δ_{L}$ ) is_____(correct to two decimal places). 41.42

Discussion

88.	An inverted U-tube manometer is used to measure the pressure difference between two pipes A and B, as shown in the figure. Pipe A is carrying oil(specific gravity=0.8) and pipe B is carrying water. The densities of air and water are 1.16 kg/m3 and 1000 kg/m3, respectively. The pressure difference between pipes A and B is _____kPa.Acceleration due to gravity:g = 10 m/s2 -2.199
Answer» An inverted U-tube manometer is used to measure the pressure difference between two pipes A and B, as shown in the figure. Pipe A is carrying oil(specific gravity=0.8) and pipe B is carrying water. The densities of air and water are 1.16 kg/ $m^{3}$ and 1000 kg/ $m^{3}$ , respectively. The pressure difference between pipes A and B is _____kPa. Acceleration due to gravity:g = 10 m/ $s^{2}$ -2.199

Discussion

89.	The velocity in m/s at a point in a two-dimensional flow is a given as →V=2^i+3^j. The equation of the stream line passing through the point is
Answer» The velocity in m/s at a point in a two-dimensional flow is a given as $\to V$ $= 2^i + 3^j$ . The equation of the stream line passing through the point is

Discussion

90.	The weight density of fluid in a container varies with depth as given under γ=0.2h2+0.1h+8.2, where h is in m and γ is in kN/m3. The pressure (gauge in kPa) at a depth 15m will be :
Answer» The weight density of fluid in a container varies with depth as given under $γ = 0.2 h^{2} + 0.1 h + 8.2$ , where h is in m and $γ$ is in $k N / m^{3}$ . The pressure (gauge in kPa) at a depth 15m will be :

Discussion

91.	For air flow over a flat plate, velocity (U) and boundary layer thickness (δ) can be expressed respectively, asuu∞=32yδ−12(yδ)3; δ=4.64x√RexIf the free stream velocity is 2 m/s and air has kinematic viscosity of 1.5×10−5m2/s and density of 1.23 kg/m3, the wall shear stress at x = 1 m, is
Answer» For air flow over a flat plate, velocity (U) and boundary layer thickness ( $δ$ ) can be expressed respectively, as $\frac{u}{u_{\infty}} = \frac{3}{2} \frac{y}{δ} - \frac{1}{2} {(\frac{y}{δ})}^{3};$ $δ = \frac{4.64 x}{\sqrt{R e_{x}}}$ If the free stream velocity is 2 m/s and air has kinematic viscosity of 1.5 $\times 10^{- 5} m^{2} / s$ and density of 1.23 kg/ $m^{3}$ , the wall shear stress at x = 1 m, is

Discussion

92.	In a 4 cm diameter pipeline carrying laminar flow of a liquid with μ=1.6 centipoise, the velocity at the axis is 2 m/s. What is the shear stress midway between the wall and the axis?
Answer» In a 4 cm diameter pipeline carrying laminar flow of a liquid with $μ = 1.6$ centipoise, the velocity at the axis is 2 m/s. What is the shear stress midway between the wall and the axis?

Discussion

93.	Water (density 1000 kg/m3) flows through an inclined pipe of uniform diameter. The velocity, pressure and elevation at section A are VA=3.2 m/s, pA=186 kPa and ZA=24.5 m respectively, and those at section B are VB=3.2 m/s, PB=260 kPa and ZB=9.1 m, respectively. If acceleration due to gravity is 10 m/s2 then the head lost due to friction is______m (round off to one decimal plac).8
Answer» Water (density 1000 $k g / m^{3})$ flows through an inclined pipe of uniform diameter. The velocity, pressure and elevation at section A are $V_{A} = 3.2 m / s, p_{A} = 186 k P a$ and $Z_{A} = 24.5 m$ respectively, and those at section B are $V_{B} = 3.2 m / s, P_{B} = 260 k P a a n d Z_{B} = 9.1 m,$ respectively. If acceleration due to gravity is $10 m / s^{2}$ then the head lost due to friction is______m (round off to one decimal plac). 8

Discussion

94.	In an iceberg, 15% of the volume projects above the sea surface. If the specific weight of sea water is 10.5 kN/m3, the specific weight of iceberg in kN/m3 is
Answer» In an iceberg, 15% of the volume projects above the sea surface. If the specific weight of sea water is 10.5 kN/m $^{3}$ , the specific weight of iceberg in kN/m $^{3}$ is

Discussion

95.	The diameter of the droplet is 0.075 mm. What is the intensity of pressure (N/sq.cm) developed in the droplet by the surface tension of 0.000075 N/mm?
Answer» The diameter of the droplet is 0.075 mm. What is the intensity of pressure (N/sq.cm) developed in the droplet by the surface tension of 0.000075 N/mm?

Discussion

96.	Which one of the following gives the lift force FL produced on a rotating circular cylinder per unit length in a uniform flow ?Where, u = free stream velocityΓ=circulationρ=density of the fluid
Answer» Which one of the following gives the lift force $F_{L}$ produced on a rotating circular cylinder per unit length in a uniform flow ? Where, u = free stream velocity $Γ = c i r c u l a t i o n$ $ρ = d e n s i t y o f t h e f l u i d$

Discussion

97.	Water flows through a pipe of diameter 0.30 m. What would be the velocity V for the conditions shown in the figure below?1.084
Answer» Water flows through a pipe of diameter 0.30 m. What would be the velocity V for the conditions shown in the figure below? 1.084

Discussion

98.	Calculate the kinematic viscosity (stokes) of the fluid if the dynamic viscosity of fluid is 0.5 poise and specific gravity is 0.4?
Answer» Calculate the kinematic viscosity (stokes) of the fluid if the dynamic viscosity of fluid is 0.5 poise and specific gravity is 0.4?

Discussion

99.	An upward flow of oil (mass density 800 kg/m3, dynamic viscosity 0.8 kg/m-s) takes place under laminar conditions in an inclined pipe of 0.1 m diameter as shown in the figure. The pressures at sections 1 and 2 are measured as p1=435 kN/m2 and p2 = 200 kN/m2. If the flow is reversed, keeping the same discharge, and the pressure at section 1 is maintained as 435 kN/m2, the pressure at section 2 is equal to
Answer» An upward flow of oil (mass density 800 kg/m $^{3},$ dynamic viscosity 0.8 kg/m-s) takes place under laminar conditions in an inclined pipe of 0.1 m diameter as shown in the figure. The pressures at sections 1 and 2 are measured as $p_{1} = 435 k N / m^{2}$ and $p_{2} = 200 k N / m^{2}$ . If the flow is reversed, keeping the same discharge, and the pressure at section 1 is maintained as $435 k N / m^{2}$ , the pressure at section 2 is equal to

Discussion

Explore topic-wise InterviewSolutions in .

Consider a laminar flow at zero incidence over a flat plate.The shear stress at the wall is denoted by τw. The axial position x1 andx2 on the plate are measured from the leading edge in the direction of flow.If x2&gt;x1,then

The relation that must hold for the flow to be irrotational is

The overall drag coefficient of an aircraft of weight W and wing area S is given by CD=a+bC2LWhere 'a' and 'b' are constants. The maximum drag in horizontal flight will be

An aluminium alloy (density 2600 kg/m3) casting is to be produced. A cylindrical hole of 100 mm diameter and 100 mm length is made in the casting using sand core (density 1600 kg/m3) . The net buoyancy force (in Newton) acting on the core is_____7.7

Water flows through pipe with a velocity given by→V=(4t+x+y)^j m/s,where ^j is the unit vector in the y direction, t(>0) is in second, and x and y are in meters. The magnitude of total acceleration at the point (x,y)= (1,1) at t=2s is_____ m/s2 3

Euler number or pressure coefficient may be represented as (notations have their usual meanings)

Three parallel pipes connected at the two ends have flow-rates Q1,Q2 and Q3 respectively and the corresponding frictional head losses are hL1,hL2, and hL3 respectively. The correct expressions for total flow rate (Q) and frictional head loss across the two ends (hL) are

Air (ρ=1.2kg/m3 and kinematic viscosity, v=2×10−5m2/s ) with a velocity of 2 m/s flows over the top surface of a flat plate of length 2.5 m. If the average value of friction coefficient is Cf=1.328√Rex, the total drag force (in N) per unit width of the plate is_________0.0159

In a laminar boundary layer, the velocity distribution can be assumed to be given, in usual notations, asuv=yδWhich one of the following is the correct experession for the displacement thickness (δ∗) for this boundary layer?

The friction factor (f), in terms of boundary shear stress (τ0) is given by ρ = mass density,V= mean velocity

A right circular cylinder, open at the top, is full of water. It is rotated about the vertical axis at such a speed that half the liquid spills out. The pressure at the centre of the bottom would be

The flow in a channel is laminar and Reynold′s number is given by 1200 .What is the friction factor for the channel?

A river model is constructed to a horizontal scale of 1 : 1000 and a vertical scale of 1 : 100. A model discharge of 0.1 m3/s would correspond to a discharge in the prototype, of what magnitude?

Which one of the following can be a set of velocity components of a two-dimensional flow?

The discharge in m3/s for laminar flow through a pipe of diameter 0.04 m having a centre line velocity of 1.5m/s is

What is the streamline equation passing through (1,1) for the following flow.V=3xi−3yj

In model similarity, if gravitational and inertial forces are the only important forces, then what is the discharge ratio?Where Lr = ratio of length dimension.

The velocity profile of a fully developed laminar flow in a straight circular pipe, as shown in the figure,given by the expressionu(r)=R24μ(∂p∂x)(1−r2R2)where ∂p∂x is a constantThe average velocity of fluid in the pipe is

Three reservoirs A, B and C are interconnected by pipes as shown in the given figure. Water surface elevations in the reservoirs and the piezometric level at the junction D are also indicated in the figure.Flow Q1,Q2 and Q3 are related as

Consider a flow through a nozzle, as shown in the figure belowThe air flow is steady, incompressible and inviscid. The density of air is 1.23 kg/m3. The pressure difference (p1−patm) is ______kPa (round off to the nearest integer).1.52

The unit of dynamic viscosity of a fluid is

A cylindrical body of cross-sectional area A, height H and density ρs′ is immersed to a depth h in a liquid of density ρ, and tied to the bottom with a string. The tension in the string is

A plane flow has velocity components u=xT1, v=−yT2 and w=0 along x, y and z directions respectively, where T1(≠0) and T2(≠0) are constants having the dimension of time. The given flow is incompressible if

X-component of velocity in two dimensional incompressible flow is given byu=2y2+6xy. If the Y-component of velocity v is zero at y =0, the expression for Y-component of velocity is given by

If the capillary rise of water in a 1 mm diameter tube is 3 cm, the height of capillary rise of water in a 0.2 mm diameter tube in cm will be -

A symmetrical right-circular cone of wood floats in fresh water with axis vertical and the apex down. The axial height of the cone is 1 unit. The submerged portion has a height h, measured upwards from the apex. What would be the height of the centre of buoyancy from the apex?

An equilateral triangular plate is immersed in water as shown in the figure below. The centre of pressure below the water surface is at depth of

What should be the angle of divergence in a venturimeter to avoid the flow separation ?

The velocity in m/s at a point in a two-dimensional flow is a given as →V=2^i+3^j. The equation of the stream line passing through the point is

The weight density of fluid in a container varies with depth as given under γ=0.2h2+0.1h+8.2, where h is in m and γ is in kN/m3. The pressure (gauge in kPa) at a depth 15m will be :

In a 4 cm diameter pipeline carrying laminar flow of a liquid with μ=1.6 centipoise, the velocity at the axis is 2 m/s. What is the shear stress midway between the wall and the axis?

In an iceberg, 15% of the volume projects above the sea surface. If the specific weight of sea water is 10.5 kN/m3, the specific weight of iceberg in kN/m3 is

The diameter of the droplet is 0.075 mm. What is the intensity of pressure (N/sq.cm) developed in the droplet by the surface tension of 0.000075 N/mm?

Which one of the following gives the lift force FL produced on a rotating circular cylinder per unit length in a uniform flow ?Where, u = free stream velocityΓ=circulationρ=density of the fluid

Water flows through a pipe of diameter 0.30 m. What would be the velocity V for the conditions shown in the figure below?1.084

Calculate the kinematic viscosity (stokes) of the fluid if the dynamic viscosity of fluid is 0.5 poise and specific gravity is 0.4?

Consider a laminar flow at zero incidence over a flat plate.The shear stress at the wall is denoted by τw. The axial position x1 andx2 on the plate are measured from the leading edge in the direction of flow.If x2>x1,then