Simulation Forums

Find Simulation answers, share expertise, and connect with your peers

Simulation CFD


wall film coefficient in natural convection

91 Views, 3 Replies
12/19/2017 10:21 AM

Hi, 

since we know that the LOCAL  film coefficient (h) for a fluid flowing over a constant temp. plate.

can be Obtained from the similarity solution at ɳ= 0. and the average value of h is the integration of the local value of 

h along the plate length.

can we consider the value of wall film coefficient that we get from wall calculator in cfd as the average value of h also? 

 


Report Inappropriate Content
Message 1 of 3 ( Views: 91 )

Re: wall film coefficient in natural convection

12/19/2017 2:53 PM

I am sure you are right! The wall calculator will integrate local values over the surface of the wall. 

 

You will have to explain a bit more about what you mean by a similarity solution as I haven't heard of that (always keen to learn though).

 


David Short
Technical Support Specialist, Simulation

Report Inappropriate Content
Message 2 of 3 ( Views: 75 )

Re: wall film coefficient in natural convection

12/19/2017 5:05 PM

sounds nice... in this case, no need to worry about driving Nusselt number or h relations...magic

 

the similarty solution is an exact solution for the conversation equation in case of heat convection 

the idea is to represent the conversation equation by one variable instead of velocity components orders 

to get an ordinary differential equation instead of PDE. we need also to defend the boundary conditions in

term of similarity variables. 

I'm  watching  this online course these days, you can also:

 

 https://www.youtube.com/watch?v=XEKc7-KKBwc&t=191s


Report Inappropriate Content
Message 3 of 3 ( Views: 71 )