In case of damaged prestressed concrete I girders which are used for restoring strength?
1 answer:
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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
