In the low Reynolds number region, the drag force on a sphere is proportional to

The power number for a stirred tank becomes constant at high Reynolds number. In this limit, the variation of power input with impeller rotational speed (N) is proportional to

A

N°

B

N¹

C

N²

D

N³

Creeping flow around a sphere is defined, when particle Reynolds number is

A

[

A.

B.

B

> 2.5

In which of the following the friction drag is generally larger than pressure drag?

A

a circular disc or plate held normal to flow

B

a sphere

C

a cylinder

D

an airfoil

The ratio of wall drag to total drag in the Stoke's law range is

A

0.5

B

1

C

$$\frac{1}{3}$$

D

$$\frac{2}{3}$$

The ratio of the wall drag to the form drag in the Stoke's law range (for motion of spherical particles in a stationary fluid) is

A

0.5

B

1

C

2

D

0.33

In which of the following body shapes, the pressure drag is large compared to the friction drag?

A

Stream line body

B

Two dimensional body

C

Bluff body

D

None of these

গ্রেডিয়েন্ট মধ্যবিন্দুর অবস্থান নির্ধারণ করা যায়-i. নির্ধারণীসূচক সংখ্যা লিখেii. আইকনটি ডানে বায়ে drag করে iii. মুক্ত টুলের সাহায্যে drag করেনিচের কোনটি সঠিক?

A

i ও ii

B

i ও iii

C

ii ও iii

D

i, ii ও iii

For a sphere falling in the constant drag co-efficient regime, its terminal velocity depends on its diameter (d) as

A

d

B

$$\sqrt {\text{d}} $$

C

d²

D

$$\frac{1}{{\text{d}}}$$

Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is

A

>10

B

>100

At low Reynolds number

A

Viscous forces are unimportant

B

Viscous forces control

C

Viscous forces control and inertial forces are unimportant

D

Gravity forces control

In the low Reynolds number region, the drag force on a sphere is proportional to

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