Skip to main content
WeiShan Ng's user avatar
WeiShan Ng's user avatar
WeiShan Ng's user avatar
WeiShan Ng
  • Member for 8 years, 4 months
  • Last seen more than a month ago
awarded
awarded
awarded
awarded
comment
Shear stress and surface heat transfer rate with various Pr values
@ChesterMiller Really thank you for your time in explaining all these to me!
comment
Shear stress and surface heat transfer rate with various Pr values
For the second part, using the definition of heat transfer coefficient $h$ and thermal conductivity: $$\dot{q} = h(T_{wall} - T_{mean}) \\ \dot{q} = k\left( -\frac{\partial T}{\partial y} \right)_{y=0}$$ we will have the relation $$\frac{h}{k}= \frac{\left( -\frac{\partial T}{\partial y} \right)_{y=0}}{T_{wall} - T_{mean}}=\mathrm{constant}$$ So if using the equation of $Pr = c_p \mu /k$, then when Pr increases, k decreases. But when k decreases, $\left( -\frac{\partial T}{\partial y} \right)_{y=0}$ increases. Is this what it supposed to be?
comment
Shear stress and surface heat transfer rate with various Pr values
@ChesterMiller Hi, can you please guide me through the reasoning? For the first part, which we assuming temperature-independent viscosity, do we also have the same velocity profile for all of the Pr values, and we have the same momentum diffusivity for different Pr?
Loading…
comment
Fluid dynamics - boundary later equation $f'''+ff''-f'^2+\theta = 0$ and $\theta''+Prf\theta' = 0$
@Emil You did point me to the right direction! Thank you!!!It's the stagnation point of free convection boundary layer flow on a horizontal cylinder. url:core.ac.uk/download/pdf/159188580.pdf
Loading…
awarded
Loading…
awarded
comment
Why don't we need to do the error calculations for all the repeated measurements?
Hi, may I know how do you get to the last expression?
Loading…
comment
comment
Number of microscopic states which have the same set of occupation numbers
It turns out I misunderstood the statement. At first I thought "number of states with the same set of $n_k$ " means "how many k will have the same number of $n_k$", now I realize it actually means the combinatorics of the states...