Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

Proper answer is D because if we think as straight line by considering u=f(x), it may have two components with respect to a reference point it means it represent 2d flow. So answer is D.

It is either straight or one dimensional.

The flow is flow in the direction of ''x'' co-ordinate. It flow contain only 'x'co-ordinate.

Please tell me the correct answer.

ANS IS D ONLY.

Straight line is a 2d dimension.

One-dimensional flow.

All the flow parameters may be expressed as functions of time and one space coordinate only.

The single space coordinate is usually the distance measured along the centre-line (not necessarily straight) in which the fluid is flowing.

Example: the flow in a pipe is considered one-dimensional when variations of pressure and velocity occur along the length of the pipe, but any variation over the cross-section is assumed negligible.

In reality, flow is never one-dimensional because viscosity causes the velocity to decrease to zero at the solid boundaries.

If however, the non-uniformity of the actual flow is not too great, valuable results may often be obtained from a "one-dimensional analysis".

The average values of the flow parameters at any given section (perpendicular to the flow) are assumed to be applied to the entire flow at that section.

One dimension means there is no turbulent flow.

Answer will be D.

One dimensional flow mean the flow which is in a straight line.

Answer B is correct.

Both B & D are correct as if the flow is one dimensional it will flow in a straight line. As one dimension always represents a single coordinate, i.e., U=f(x) if we consider flow along the x direction. But this explanation follows option D too as if the flow is considered along line x=y then with respect to the coordinate system which is tilted by 45 degrees it is a flow along the axis and hence again in a straight line.

So the velocity will be given as U=f(x') where x' would be the x direction in transformed axis and hence flow in a single direction is also a one-dimensional flow.