The cross section area of the other position which supports an object ...
Solution:
Given data:
Mass of the object (m) = 2000 kg
Boundary layer thickness (δ) = 1 mm
Reynolds number (Re) = 1000
Velocity of the fluid (v) is increased by a factor of 4
Reynolds number:
Reynolds number is a dimensionless quantity that determines the type of flow (laminar or turbulent) in a fluid. It is given by the formula:
Re = ρvd/μ
Where,
ρ = density of the fluid
v = velocity of the fluid
d = characteristic length
μ = dynamic viscosity of the fluid
Bernoulli's equation:
Bernoulli's equation describes the conservation of energy in fluid flow. It is given by the formula:
P + 0.5ρv^2 + ρgh = constant
Where,
P = pressure of the fluid
ρ = density of the fluid
v = velocity of the fluid
g = acceleration due to gravity
h = height above a reference point
Boundary layer thickness:
Boundary layer thickness is the distance between the solid surface and the point where the flow velocity reaches 99% of the free-stream velocity. It is influenced by factors such as Reynolds number and surface roughness.
Effect of increased velocity:
When the velocity of the fluid alone is increased by a factor of 4, the Reynolds number will also increase by the same factor. This is because Reynolds number is directly proportional to the velocity of the fluid.
Calculation:
1. Given that the Reynolds number (Re) is 1000, we can find the characteristic length (d) using the formula:
Re = ρvd/μ
1000 = ρv(1)/μ
2. Assuming the density (ρ) and dynamic viscosity (μ) of the fluid to be constant, we can rewrite the formula as:
v = Reμ/(ρd)
v = 1000μ/(ρd)
3. Let the initial velocity be v1 and the final velocity be v2. According to the given information, v2 = 4v1.
4. Substituting the values of v1 and v2 in the equation obtained in step 2, we get:
v2 = 1000μ/(ρd)
4v1 = 1000μ/(ρd)
5. Rearranging the equation, we can solve for v1:
v1 = (1000μ/(ρd))/4
v1 = 250μ/(ρd)
6. Since the Reynolds number is directly proportional to the velocity, we can write:
Re2 = Re1 * (v2/v1)
Re2 = 1000 * (4v1/v1)
Re2 = 4000
7. Now, let's calculate the boundary layer thickness at the same location using the new Reynolds number (Re2).
Re2 = ρv2d/μ
4000 = ρv2(1)/μ
8. Assuming the density (ρ) and dynamic viscosity (μ) of the fluid to be constant, we can rewrite the formula as:
v2 = Re2μ/(ρd)
v2 = 4000μ/(ρd)
9. Substituting the values of v2 in