Physics Of Kinematic Viscosity

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Bernoulli’s theorem states that the total energy of an incompressible, in-viscid fluid, either liquid or gas, flowing at a steady state from one point to another remains constant throughout the displacement. Bernoulli’s equation recognizes that an increase in kinetic energy (velocity) triggers a decrease in pressure within the fluid. Bernoulli’s equation relates the pressure at a point in the fluid to its position and velocity.
P_2+ρ 〖u_2〗^2/2+(ρgh_2 )=P_1+ρ 〖u_1〗^2/2+(ρgh_1 ) (1)
Both P_1 and P_2 represent pressure at points one and two, ρ and u are fluid characteristics density and velocity, g represents the gravity constant 9.81m/s^2 and h_1 and h_2 signify the heights at points one and two.
Viscosity is a measure of a fluid’s resistance to flow. An example of this being the comparison between honey and water; flowing honey through a pipe is a slower process then repeating the same process with water this indicates honey has a higher viscosity level compared with water. Viscous properties tend to steady and organise the flow of a fluid however excessive fluid inertia tends to unsettle flow leading to more disordered turbulent behaviour. Kinematic viscosity is a dimensionless number measuring the ratio of absolute viscosity to density.
In practice, fluids experience friction against surface area. The friction generated corresponds to an energy transformation from kinetic → heat and results in a –ΔP over the length of the fluid flow. We denote this energy loss between point 1 and point 2 as ΔPfriction and account for it experimentally, depending on whether the flow is described as laminar or turbulent by the Reynolds number. Reynolds number is determined by the ratio of inertia forces to viscous forces.
Re=ρuD/μ ...

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...on using the data P1 = P2 = Patm and U1 = U2 ≈ 0 m∕s:
〖∆P〗_pump/ρ=〖∆P〗_f/ρ+ gz_2-gz_1
In order to determine a system curve the flow rate must be determined at a range of points. Plotting both the system curve and pump curve together enables the operating point to be found which corresponds to the ideal flow rate. The pump curve can be determined experimentally by modifying the system curve one of two ways; either opening a valve or changing the height difference.
In order to study the aspects of fluid mechanics that need to be taken into account when constructing our cooling tower, a breakdown of different behaviours of fluids under different conditions must be performed and tested against the flow rate. The experimental design would have to explore the influence of the length of the flow pipe as well as the density and temperature on the flow rate of the fluid.

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