Fluid Mechanics

The Effectiveness-NTU method of heat exchanger design requires inlet temperatures of the fluids while the LMTD method requires both inlet and outlet temperatures for both fluids Hence A is true but R is false as the LMTD method does not require only inlet and outlet temperatures for both fluids but other parameters as well

In a convergent-divergent nozzle the pressure at the throat is equal to the critical pressure The flow is subsonic in the convergent section and becomes supersonic in the divergent section making statements C and D true Statement A is false as the pressure in the divergent section is lower than in the convergent section

Statement A is correct because the flow is generally considered turbulent when the Reynolds number exceeds 4000 However statement R is incorrect because turbulent flow does not transition to laminar flow over a pipe’s length it remains turbulent unless external factors alter the flow

The match between the non-dimensional numbers and their ratios is as follows Reynold’s Number Inertia force to viscous force Mach Number Inertia force to gravity force Froude’s Number Inertia force to surface tension force Weber’s Number Inertia force to elastic force

Euler’s equation assumes that the fluid is non-viscous which means there is no internal friction in the fluid Statement I is true However Euler’s equation does not assume that the flow is along a streak line the flow can be more general Statement II is false

Pressure sequence valves are used to sense the hydraulic pressure in an external line and send a signal when it reaches a preset value typically used to control multiple actuators

Step 1: Define Newtonian fluid.
A Newtonian fluid is one whose viscosity remains constant regardless of the applied shear rate. The fluid obeys Newton's law of viscosity, which states: Where is the shear stress, is the dynamic viscosity, and is the shear rate. Step 2: Conclusion.
Since the fluid follows Newton's law of viscosity, it is a Newtonian fluid. Final Answer:

Step 1: Understand Bernoulli's theorem.
Bernoulli’s theorem states that for an incompressible, frictionless flow, the total mechanical energy along a streamline is constant. The total energy consists of the pressure energy, kinetic energy, and potential energy. Where is the pressure, is the density, is the velocity, and is the height. Step 2: Conclusion.
Bernoulli's theorem is based on the principle of the conservation of energy. Final Answer:

Step 1: Understanding boundary layer thickness.
For a laminar boundary layer over a flat plate, the thickness of the boundary layer at a distance from the leading edge is given by the formula: This formula is derived from the solution of the Navier-Stokes equations for laminar flow over a flat plate. Step 2: Conclusion.
The boundary layer thickness varies as for laminar flow. Final Answer: