Related Questions

The velocity at which the flow changes from laminar flow to turbulent flow is called
A Critical velocity
B Velocity of approach
C Sub-sonic velocity
D Super-sonic velocity
Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the
A Length of the pipe
B Diameter of the pipe
C Density of the fluid
D Velocity of the fluid
For pipes, turbulent flow occurs when Reynolds number is
A Less than 2000
B Between 2000 and 4000
C More than 4000
D Less than 4000
In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
A Convection
B Radiation
C Conduction
D Both convection and conduction
A flow in which __________ force is dominating over the viscosity is called turbulent flow.
A Elastic
B Surface tension
C Viscous
D Inertia
For turbulent flow of an incompressible fluid through a pipe, the flow rate Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is
A 1
B 0
C > 1
Transition from laminar flow to turbulent flow is aided by the
A Surface roughness and curvature (i.e.sharp corners)
B Vibration
C Pressure gradient and the compressibility of the flowing medium
D All of the above
For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of
A 1
B 1.74
C 6.1
D 37
For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r = pipe radius, x = distance).
A $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{x}}}{{\text{r}}}} \right)^{\frac{1}{7}}}$$
B $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {\frac{{\text{r}}}{{\text{x}}}} \right)^{\frac{1}{7}}}$$
C $$\frac{{\text{V}}}{{{{\text{V}}_{\max }}}} = {\left( {{\text{x}} \times {\text{r}}} \right)^{\frac{1}{7}}}$$
D None of these
Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as
A V1.8
B V-0.2
C V2.7
D V2

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