Previous Years GATE Questions on Boundary Layer

Solved GATE Questions on Boundary Layer

Question 1. Flow separation in a flow past a solid object is caused by

(A) A reduction of pressure to vapor pressure

(B) A negative pressure gradient

(C) A positive pressure gradient

(D) The boundary layer thickness reducing to zero

GATE-ME-2002

Hint

Question 2. If x is the distance measured from the leading edge of a flat plate, then laminar boundary layer thickness varies as

(A) 1/x

(B) 

(C) 

(D) 

GATE-ME-2002

Hint

Question 3. If there are m physical quantities and n fundamental dimensions in a particular process, the number of non-dimensional parameter is

(A) m+n

(B) 

(C) m-n

(D) m/n

GATE-ME-2002

Hint

Question 4. Consider a laminar boundary layer over a heated flat plate. The free stream velocity is. At some distance x from the leading edge the velocity boundary layer thickness is  and the thermal boundary layer thickness is . If the prandtl number is greater than 1, then

(A) 

(B) 

(C) 

(D) ) 

GATE-ME-2003

Hint

Question 5. For air flow over a plate, velocity (U) and boundary layer thickness() can be expressed respectively, as

If the free steam velocity is 2 m/s, and air has kinematic viscosity of 1.5 and density of 1.23 kg/then wall shear stress at x=1m, is

(A) 2.36

(B) 43.6

(C) 4.36

(D) 2.18

GATE-ME-2004

Hint

Statement for Linked Answer Question 6 and 7:

A smooth flat plate with a sharp leading edge is placed along a gas stream flowing at U=10 m/s. The thickness of the boundary layer at section r-s=10 mm, the breadth of the plate is 1m (onto the paper) and the density of thegas . Assume that the boundary layer is thin, two dimensional, and follows a linear velocity distribution, , at the section r-s, where y is the height from plate.

Question 6. The mass flow rate (in kg/s) across the section q-r is

(A) Zero

(B) 0.05

(C) 0.10

(D) 0.15

GATE-ME-2006

Hint

Question 7. The integrated drag force (in N) on the plate, between p-s, is :

(A) 0.67

(B) 0.33

(C) 0.17

(D) Zero

GATE-ME-2006

Hint

Question 8. A model of a hydraulic turbine is tested at head of 1/4^th of that under which the full scale turbine works. The diameter of the model is half of that of the full scale turbine. If N is the RPM of the full scale turbine, the RPM of the model will be

(A) N/4

(B) N/2

(C) N

(D) 2N

GATE-ME-2007

Hint

Question 9. Consider an incompressible laminar boundary layer flow over a flat plate of length of L, aligned with the direction of an oncoming uniform free stream. If F is the ratio of the drag force on the front half of the plate to the drag force on the rear half, then

(A) 

(B) 

(C) 

(D) 

GATE-ME-2007

Hint

Question 10. Match the following

 

(A) P-U ; Q-X ; R-V ;S-Z ; T-W

(B) P-W ; Q-X ; R-Z ; S-U; T-V

(C) P-Y ; Q-W ; R-Z ; S-U ; T-X

(D) P-Y ; Q-W ; R-Z ; S-U ; T-V

GATE-ME-2010

Hint

Question 11. A phenomenon is modeled using n dimensional variables with k primary dimensions. The number of non-dimensional variables is

(A) k

(B) n

(C) n-k

(D) n+k

GATE-ME-2010

Hint

Question 12. An incompressible fluid flows over a flat with zero pressure gradient. The boundary layer thickness is 1mm at a location where the Reynolds number is 1000. If the velocity of the fluid alone is increased by a factor 4, then boundary layer thickness at the same location, in mm will be

(A) 4

(B) 2

(C) 0.5

(D) 0.25

GATE-ME-2012

Hint

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