What shape has the lowest coefficient of drag?
streamlined symmetric airfoil
What is Mew in Reynolds number?
μ (mu) is the dynamic viscosity of the fluid (Pa·s = N·s/m2 = kg/(m·s)), ν (nu) is the kinematic viscosity (ν = μρ) (m2/s), ρ (rho) is the density of the fluid (kg/m3), W is the mass flowrate of the fluid (kg/s).
What does Reynolds number tell us?
The Reynolds number is used to determine whether a fluid is in laminar or turbulent flow. Based on the API 13D recommendations, it is assumed that a Reynolds number less than or equal to 2100 indicates laminar flow, and a Reynolds number greater than 2100 indicates turbulent flow.
What is a typical Reynolds number?
Whenever the Reynolds number is less than about 2,000, flow in a pipe is generally laminar, whereas, at values greater than 2,000, flow is usually turbulent.
What is considered a high Reynolds number?
The Reynolds number is a dimensionless number. High values of the parameter (on the order of 10 million) indicate that viscous forces are small and the flow is essentially inviscid.
How is Reynolds number useful?
The Reynolds ( Re ) number is a quantity which engineers use to estimate if a fluid flow is laminar or turbulent. This is important, because increased mixing and shearing occur in turbulent flow. This results in increased viscous losses which affects the efficiency of hydraulic machines.
How does Reynolds number effect lift and drag?
The lift-to-drag ratio increases as Reynolds number increases for both the airfoils without and with GF. This drag penalty increases with Reynolds number. At higher lift coefficients, the lift-to-drag ratio increased. Hence the lift coefficient increases for a given lift-to-drag ratio.
Is Reynolds number constant?
It is clearly seen that the critical Reynolds number for D2O is considerably higher than for water: their ratio is RD2O/RH2O = 1.15….RESULTS.
| Liquid | Critical Re | Notes |
|---|---|---|
| C2H50H | 3400 | Different pipe, different geometry of outflowing basin, and different alcohol compared to the data of Table 3. |
What is the value of Reynolds number for turbulent flow?
The Reynold Number of turbulent flow is > 4000. ∴ For turbulent flow, the value of Reynolds number is Re > 2000.
What is H in Nusselt number?
Forced convection in fully developed laminar pipe flow For fully developed internal laminar flow, the Nusselt numbers tend towards a constant value for long pipes. For internal Flow: where: Dh = Hydraulic diameter. kf = thermal conductivity of the fluid.