Hydraulics And Fluid Mechanics - Study Mode
[#61] The stress-strain relation of the newtoneon fluid is
Correct Answer
(A) linear
[#62] For pipes, turbulent flow occurs when Reynolds number is
Correct Answer
(C) more than 4000
Explanation
Solution: Reynolds number is a very important dimensionless quantity in fluid mechanics. It helps us understand whether the flow of a fluid (like water in a pipe) is smooth (laminar) or chaotic (turbulent) . Imagine water flowing through a pipe. If the flow is laminar, it's like perfectly ordered layers of water sliding smoothly over each other. Turbulent flow, on the other hand, is messy! It involves swirling, mixing, and unpredictable changes in the water's velocity. The Reynolds number (Re) is calculated using the fluid's properties (density, viscosity), its velocity, and the pipe's diameter. A higher Reynolds number means a higher velocity or a larger diameter , leading to more chaotic flow. For flow in pipes, we use a general guideline based on the Reynolds number: - Laminar flow: Re < 2000 - Transition region (between laminar and turbulent): 2000 < Re < 4000 (the flow can be either laminar or turbulent in this range) - Turbulent flow: Re > 4000 Therefore, turbulent flow in pipes occurs when the Reynolds number is more than 4000 .
[#63] Centre of buoyancy always
Correct Answer
(B) coincides with the centroid of the volume of fluid displaced
[#64] Choose the wrong statement
Correct Answer
(D) Viscosity of liquids is appreciably affected by change in pressure
(H) All floating bodies are stable
(L) he vertical component passes through the center of pressure of the volume
(P) when in equilibrium, fluids can sustain shear forces
(T) Center of buoyancy is located above the center of gravity of the displaced liquid v
[#65] Center of buoyancy is the
Correct Answer
(A) centroid of the displaced volume of fluid