2. Tech A says that a tapered roller bearing assembly has less rolling resistance than a similarly sized

In fully developed laminar flow in a circular pipe the velocity at R/2 (mid-way between the wall surface and the centerline) is

Butoxors [25]

Answer:

$u_{max} = 17.334\,\frac{m}{s}$

Explanation:

Let consider that velocity profile inside the circular pipe is:

$u(r) = 2\cdot U_{avg} \cdot \left(1 - \frac{r^{2}}{R^{2}} \right)$

The average speed at $r = \frac{1}{2} \cdot R$ is:

$U_{avg} = \frac{13\,\frac{m}{s} }{2\cdot \left(1-\frac{1}{4} \right)}$

$U_{avg} = 8.667\,\frac{m}{s}$

The velocity at the center of the pipe is:

$u_{max} = 2\cdot U_{avg}$

$u_{max} = 17.334\,\frac{m}{s}$

6 0

3 years ago

Read 2 more answers

Consider water at 27°C in parallel flow over an isothermal, 1‐m‐long flat plate with a velocity of 2 m/s. a) Plot the variation

yulyashka [42]

Answer:

i) h-bar-L = 4110 W/m^2K

ii ) h-bar-L = 4490 W/m^2K

iii) h-bar-L = 5072 W/m^2K

Explanation:

Given:-

- The temperature of water, T = 27°C

- The velocity of fluid flow, U∞ = 2m/s

- The length of the flat place, L = 1 m

Solution:-

- Using table A-6, to determine the properties of water:

Density ρ = 997 kg/m^3

Dynamic viscosity ν = 0.858*10^-6 m^2/s

Pr = 583 , k = 0.613 W/m.K

- The reynold's number for full length (L = 1m):

Re = U∞*L / ν

Re = (2)*(1) / (0.858*10^-6)

Re = 2.33*10^6

- The boundary layer is mixed with Rex,c = 5*10^5. Evaluate the critical length (xc):

xc = L* ( Rex,c / Re )

= (5*10^5 / 2.33*10^6 )

= 0.215 m

a) Using "IHT correlation tool, External Flow, Local coefficients for laminar or Turbulent flows", h (x) was evaluated and plotted with critical Reynolds number for all 3 cases: (i) 5 × 10^5, (ii) 3 × 10^5, and (iii) 0 (the flow is fully turbulent). - (See attachment 1)

b) Using "IHT correlation tool, External Flow, Average coefficients for laminar or Mixed flows", h - bar- (x) was evaluated and plotted with critical Reynolds number for all 3 cases: (i) 5 × 10^5, (ii) 3 × 10^5, and (iii) 0 (the flow is fully turbulent). - (See attachment 2)

c) The average convection coefficient for the plate can be determined from the graphs presented in (Attachments 1 and 2). Since,

h-bar-L = h-bar-x(L)

The values for the flow conditions are:

( i) h-bar-L = 4110, ii ) h-bar-L = 4490 , iii) h-bar-L = 5072 ) W/m^2K

6 0

4 years ago

A Wheatstone bridge initially has resistances equal to R1 = 200Ω, R2 = 400Ω, R3=500Ω and R4=600Ω. For an input voltage of 5V, de

Masja [62]

Answer:

A. Vo = -0.606 volts

B. Vo = -0.349 volts

Explanation:

In this question, we are asked to calculate the output voltage by analyzing the conditions given and also calculate the output voltage given that one of theses conditions changed.

Please check attachment for complete solution.