1
GATE ME 2024
+1
-0.33

Consider a hydrodynamically fully developed laminar flow through a circular pipe with the flow along the axis (i.e., z direction). In the following statements, $T$ is the temperature of the fluid, $T_w$ is the wall temperature and $T_m$ is the bulk mean temperature of the fluid. Which one of the following statements is TRUE?

A

For a thermally fully developed flow, $\frac{\partial T}{\partial z} = 0,$ always.

B

For constant wall temperature of the duct, $\frac{dT_m}{dz} =$ constant.

C

Nusselt number varies linearly along the z direction for a thermally fully developed flow.

D

For constant wall temperature $(T_w > T_m)$ of the duct, $\frac{dT_m}{dz}$ increases exponentially with distance along z direction.

2
GATE ME 2016 Set 3
+1
-0.3
Grashof number signifies the ratio of
A
inertia force to viscous force
B
buoyancy force to viscous force
C
buoyancy force to inertia force
D
inertial force to surface tension force
3
GATE ME 2015 Set 3
+1
-0.3
The ratio of momentum diffusivity $$\left( \upsilon \right)$$ to thermal diffusivity $$\left( \alpha \right),$$ is called
A
Prandtl number
B
Nusselt number
C
Biot number
D
Lewis number
4
GATE ME 2015 Set 2
+1
-0.3
In the laminar flow of air $$(Pr=0.7)$$ over a heated plate, if $$\delta$$ and $${\delta _T}$$ denote, respectively the hydrodynamic and thermal boundary layer thickness, then
A
$$\delta = {\delta _t}$$
B
$$\delta > {\delta _t}$$
C
$$\delta < {\delta _t}$$
D
$$\delta = 0$$ but $${\delta _t} \ne 0$$
GATE ME Subjects
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