2D Single Bladed VAWT Simulation with Sliding Mesh Problem

peter go · February 4, 2015, 05:29

Hi, I'm working on 2D Single Bladed VAWT (NACA 0012) with Sliding Mesh
and I have several problem:
1. how to get the good Cl value of the blade? I used force monitor and it gave me some unrealistic values such as -13.7 or 20.8
2. there's a problem in the interface as shown in the picture

can someone help me?
thank you

abuabdellah.albatal · September 5, 2015, 20:31

i need more calrification to be able to help you ...

peter go · September 6, 2015, 12:02

Thank you, but I already solve the problem

abuabdellah.albatal · September 6, 2015, 13:09

would you please send me the case file and data file, becuse i am working on relevant task and tried alot to solve my case but always give either -ve results or high +ve values higher than experimental results ..

would you please help me in that with your insights in meshing, how i can mesh the part and also the the solver -fluent- settings
do not worry i am very aware about all of that but i know there is something i do not know ...

thanks in advance ...

best wishes ...

peter go · September 6, 2015, 13:21

you just need to have a finer mesh especially in the laminar sublayer area, make sure your y+<1...then to get a good Cl value just go to the reference value and make sure the area is the same with your turbine diameter

also make sure your time step size is small enough to capture the vortex evolution

abuabdellah.albatal · September 6, 2015, 13:27

1- i tried to solve with mesh 190000 cell do you think it is good ?
2- what is the the laminar sublayer area,is it the area near the blades?
3- what is the y+ and how i become sure from y+<1?
4- regarding the area the default is 1 and mine is 1.03, okay i will put it the same ?
5- for the time step size do you think 0.001 is good ?

sorry for many questions ...

thanks alot ..

peter go · September 6, 2015, 13:36

it depends on the case and the dimension of your turbine.
the area should be your turbine diameter.
then the you have to calculate the vector manually (or using script with whatever software you have) after you get the Cl value from fluent
I think you should read about the basic theory of aerodynamics and CFD first.
you can find it there and then you can modify the equation to calculate the vector

abuabdellah.albatal · September 6, 2015, 13:59

my trubine diameter is 1.03m, the whole domain is 20m*20m
1- i am using he ansys workbench mesher
2- how i identify that the mesh efficiency is good
3- i know the y+ calculator but i don't know how to use it in the meshing or what os the desired value of the y+ .. you can suggest me the value.
4- what is the use of the wall spacing in meshing?
5- who i should use the compute from in reference values ?

i totally appreciate your effort and time
please guide me and i am very thankful ...

best wishes

peter go · September 8, 2015, 11:39

1&2. you have to do grid independency study
3,4,&5. read the manual

I don't mean to be rude but your first post said that u want to help me, now you want me to help you & I think you're too lazy to read.

read the books dude! what you're asking are the common questions!

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September 5, 2015, 20:31		#2
abuabdellah.albatal New Member abuabdellah Join Date: Jan 2012 Posts: 23 Rep Power: 13	i need more calrification to be able to help you ...

September 6, 2015, 12:02		#3
peter go New Member Join Date: Nov 2014 Posts: 6 Rep Power: 12	Thank you, but I already solve the problem

September 6, 2015, 13:09		#4
abuabdellah.albatal New Member abuabdellah Join Date: Jan 2012 Posts: 23 Rep Power: 13	would you please send me the case file and data file, becuse i am working on relevant task and tried alot to solve my case but always give either -ve results or high +ve values higher than experimental results .. would you please help me in that with your insights in meshing, how i can mesh the part and also the the solver -fluent- settings do not worry i am very aware about all of that but i know there is something i do not know ... thanks in advance ... best wishes ...

September 6, 2015, 13:21		#5
peter go New Member Join Date: Nov 2014 Posts: 6 Rep Power: 12	you just need to have a finer mesh especially in the laminar sublayer area, make sure your y+<1...then to get a good Cl value just go to the reference value and make sure the area is the same with your turbine diameter also make sure your time step size is small enough to capture the vortex evolution

September 6, 2015, 13:27		#6
abuabdellah.albatal New Member abuabdellah Join Date: Jan 2012 Posts: 23 Rep Power: 13	1- i tried to solve with mesh 190000 cell do you think it is good ? 2- what is the the laminar sublayer area,is it the area near the blades? 3- what is the y+ and how i become sure from y+<1? 4- regarding the area the default is 1 and mine is 1.03, okay i will put it the same ? 5- for the time step size do you think 0.001 is good ? sorry for many questions ... thanks alot ..

September 6, 2015, 13:36		#7
peter go New Member Join Date: Nov 2014 Posts: 6 Rep Power: 12	it depends on the case and the dimension of your turbine. the area should be your turbine diameter. then the you have to calculate the vector manually (or using script with whatever software you have) after you get the Cl value from fluent I think you should read about the basic theory of aerodynamics and CFD first. you can find it there and then you can modify the equation to calculate the vector

September 6, 2015, 13:59		#8
abuabdellah.albatal New Member abuabdellah Join Date: Jan 2012 Posts: 23 Rep Power: 13	my trubine diameter is 1.03m, the whole domain is 20m*20m 1- i am using he ansys workbench mesher 2- how i identify that the mesh efficiency is good 3- i know the y+ calculator but i don't know how to use it in the meshing or what os the desired value of the y+ .. you can suggest me the value. 4- what is the use of the wall spacing in meshing? 5- who i should use the compute from in reference values ? i totally appreciate your effort and time please guide me and i am very thankful ... best wishes

September 8, 2015, 11:39		#9
peter go New Member Join Date: Nov 2014 Posts: 6 Rep Power: 12	1&2. you have to do grid independency study 3,4,&5. read the manual I don't mean to be rude but your first post said that u want to help me, now you want me to help you & I think you're too lazy to read. read the books dude! what you're asking are the common questions!