Civil Engineering - Hydraulics - Discussion

Discussion Forum : Hydraulics - Section 1 (Q.No. 16)
16.
The ratio of maximum velocity to average velocity of viscous fluid through a circular pipe is
0.5
0.75
1.25
2.00
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 1 of 3.

Michelle Mencias said:   8 years ago
If you solve this question for the laminar case the maximum velocity will be 2*uavg, 2*uavg, this means chaotic system dissipate more energy due to viscous effect. And can be related to the natural phenomenon as big eddies that form in the fluid consumes energy in form of angular velocity or vorticity and get converted to smaller eddies and eventually die out dissipating energy to the environment.

Mesbah Ullah said:   4 years ago
The question is not clear where it is laminar or turbulant flow for oil in case of laminar it is 2 see Hagen–Poiseuille equation.

For some cases, it may 0.5. One thing must be clear that avg velocity is half of the max velocity and max velocity always exist at the centre of pipe.
(1)

BugtiMehdi said:   2 years ago
For a fully developed laminar viscous flow through a circular pipe, the maximum velocity is equal to twice the average velocity.
Vavrg = 2 × Vmax.
Vavrg/Vmax = 2.
(1)

Bhanu said:   7 years ago
Max.velocity= - 1 ÷ 4u (dp ÷ dx)*r^2
And avg. Velocity = -1 ÷8u (dp ÷ dx)*-r^2, so that the ratio will be = 2.

Venkatesh naidu said:   8 years ago
In laminar flow, for pipes max.velocity= 2*avg.velocity.
For parallel plates max.velocity=1.50*avg.velocity.
(1)

Harshit said:   6 years ago
Vmax/Vavg = 2 for laminar circular pipe flow.
.
.
.
Vmax/Vavg = 3/2 for laminar fixed plate flow.
(3)

Sahil Sanjeev Salvi said:   8 years ago
Max. Velocity = 2 Avg. Velocity --> For Pipe.
Max. Velocity = 1.5 Avg. Velocity --> For Plate.

Parsolian said:   5 years ago
Umax/U=[1+1.43F^.5].
Which is;
Turbulent = 1.2-1.25.
Laminare = 2.
b/w plates = 1.5.
(1)

Mahesh Walde said:   8 years ago
Boss maximum velocity is 0.97 and avg velocity is 0.81 then how become its ratio 2?

Tjs said:   9 years ago
Umax = -1/4u (Something which writing difficult).

And Uavg.= -1/8u.


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