I am new in STAR and need your help pls.

Karen Martirosyan · September 5, 2020, 05:30

hi everyone. Could you help me pls find some special literature where I can find
everything about the net. Net independence, net quality .how can i make perfect mashing .How many tipe of net there are etc.
I have to completely investigate Naca 2209 wings and find the best solution for net and mashing.Actually the Tutorial Guide is not enough. My time is limited

I will be grateful for any help.

fluid23 · September 9, 2020, 08:10

That is an incredibly open ended question and one that probably doesn't have a simple answer. The 'best' mesh solution really depends on what you are trying to get our of your model. What does 'best' even mean? Most accurate? Fewest cells?

I suggest that you try and frame the problem a little better.

Karen Martirosyan · September 10, 2020, 04:08

I study the NACA 2209 wing.actually my job is to study different nets with different angles of attack and to find out the best computational domain.study the net independence.i have to find the best net where the iterations don't change anymore.that's the goal.to do all this my professor said that it should be a special book where i can find everything about net.actually they want me to find this book by myself
I will be very thankful for every little help.

cwl · September 10, 2020, 08:31

If your professor doesn't provide you with books or references .. why would you need such professor %>

PS Correct word is "mesh", not "net".

SimulatorMaster · September 10, 2020, 20:23

I have quite a bit experience with simulating airfoils. I can tell you the steps I took, though, I cant really explain you the Fundamentals of Star CCM+ here. You can check out the tutorial video my professor made in this link:

https://www.youtube.com/watch?v=Y-clr8RwnQw

Now first of all, you obviously need the CAD of the airfoil, NACA 2209. There are sites where you can obtain the information about various kinds of airfoils and where they are used. I advice you to learn how the numbering system works for the airfoils. Anyway, the site I have used to start the CAD is www.airfoiltool.com. This is where you can put the numbers in and create a plot for your airfoil. Click on the "4 Digit airfoils" link on the left hand side bar (the numbering is in 4 digits 2209).

After you are done with plugging in the numbers, you can extract the coordinates of your airfoil to EXCEL. This can be done by clicking on "Send to Airfoil Plotter" and then clicking "CSV file of coordinates." With these coordinates you can start drawing your airfoil.

You have to play around with the numbers sometimes; hence, dont give up you will figure it out.

Now more on how the sim will go. There are various tutorials available on Star-CCM+. (You may have to ask these from your prof.) If you have these files, open Star CCM+ and click help tab on click on "tutorial guide". ( It will direct you to Simcenter on your default browser) Now, go to Simcenter Star-CCM+ --->Tutorials---> Compressible Flow---> Take a look at the ones with Airfoil. (Overset Mesh will allow you to rotate your airfoil to analyze different angles of attacks with various advantages, I, again, advise you to read it.)

You need to pay attention to the flow over the wing and its wake (flow behind the wing). For this reason, your mesh (or 'net' as you call it) must be fine (smaller mesh) around the wing and behind it as flow will be complicated around those regions. The tutorials should give you a small idea about how to mesh. With more mesh, your solve time will significantly increase, so start with coarse (large mesh size) mesh and see how the simulations responds. (Your residuals must go below 10^-3 as a rule of thumb.)

Moreover, I advise you to research the topics transonic flow, super sonic flow, types of shock waves, flow separation, turbulence generated to prevent flow separation over the wings of aircraft...(all I can remember when I did my project). Also know what Mach number is. Perhaps you can make comparison between this airfoil and the modern airfoils used for military fighter jets. (Thats what I did for my project. Analyzed flow over FW190 wing and F35 wing)

You may read alot of articles and research done by engineers/scientists. You wont have access to many of the research without paying money. Hence, use scihub.tw (plug in the DOI, which is generally provided with the paper you want to read and paste it to sci-hub.tw ) This will grant you the permission to read and download the paper you like.

Feel free to ask questions as you proceed. Also, if you need books, try library genesis (type it on google). It will you give an access to books you would like to download. ( For example; Transonic Flow (its a book) ) If you would like to get into turbulence,, try Davidsons Turbulence: An Intro to... And so on.

Karen Martirosyan · September 14, 2020, 13:35

Thank you soooo much my friend.It was really helpfull .I found what i needed.

September 5, 2020, 05:30	I am new in STAR and need your help pls.	#1
Karen Martirosyan New Member Deutschland Join Date: Sep 2020 Posts: 11 Rep Power: 5	hi everyone. Could you help me pls find some special literature where I can find everything about the net. Net independence, net quality .how can i make perfect mashing .How many tipe of net there are etc. I have to completely investigate Naca 2209 wings and find the best solution for net and mashing.Actually the Tutorial Guide is not enough. My time is limited I will be grateful for any help.

September 10, 2020, 04:08	Thank you for answering	#3
Karen Martirosyan New Member Deutschland Join Date: Sep 2020 Posts: 11 Rep Power: 5	I study the NACA 2209 wing.actually my job is to study different nets with different angles of attack and to find out the best computational domain.study the net independence.i have to find the best net where the iterations don't change anymore.that's the goal.to do all this my professor said that it should be a special book where i can find everything about net.actually they want me to find this book by myself I will be very thankful for every little help.

September 10, 2020, 20:23		#5
SimulatorMaster New Member Onur Join Date: Dec 2018 Location: Turkey Posts: 25 Rep Power: 7	I have quite a bit experience with simulating airfoils. I can tell you the steps I took, though, I cant really explain you the Fundamentals of Star CCM+ here. You can check out the tutorial video my professor made in this link: https://www.youtube.com/watch?v=Y-clr8RwnQw Now first of all, you obviously need the CAD of the airfoil, NACA 2209. There are sites where you can obtain the information about various kinds of airfoils and where they are used. I advice you to learn how the numbering system works for the airfoils. Anyway, the site I have used to start the CAD is www.airfoiltool.com. This is where you can put the numbers in and create a plot for your airfoil. Click on the "4 Digit airfoils" link on the left hand side bar (the numbering is in 4 digits 2209). After you are done with plugging in the numbers, you can extract the coordinates of your airfoil to EXCEL. This can be done by clicking on "Send to Airfoil Plotter" and then clicking "CSV file of coordinates." With these coordinates you can start drawing your airfoil. You have to play around with the numbers sometimes; hence, dont give up you will figure it out. Now more on how the sim will go. There are various tutorials available on Star-CCM+. (You may have to ask these from your prof.) If you have these files, open Star CCM+ and click help tab on click on "tutorial guide". ( It will direct you to Simcenter on your default browser) Now, go to Simcenter Star-CCM+ --->Tutorials---> Compressible Flow---> Take a look at the ones with Airfoil. (Overset Mesh will allow you to rotate your airfoil to analyze different angles of attacks with various advantages, I, again, advise you to read it.) You need to pay attention to the flow over the wing and its wake (flow behind the wing). For this reason, your mesh (or 'net' as you call it) must be fine (smaller mesh) around the wing and behind it as flow will be complicated around those regions. The tutorials should give you a small idea about how to mesh. With more mesh, your solve time will significantly increase, so start with coarse (large mesh size) mesh and see how the simulations responds. (Your residuals must go below 10^-3 as a rule of thumb.) Moreover, I advise you to research the topics transonic flow, super sonic flow, types of shock waves, flow separation, turbulence generated to prevent flow separation over the wings of aircraft...(all I can remember when I did my project). Also know what Mach number is. Perhaps you can make comparison between this airfoil and the modern airfoils used for military fighter jets. (Thats what I did for my project. Analyzed flow over FW190 wing and F35 wing) You may read alot of articles and research done by engineers/scientists. You wont have access to many of the research without paying money. Hence, use scihub.tw (plug in the DOI, which is generally provided with the paper you want to read and paste it to sci-hub.tw ) This will grant you the permission to read and download the paper you like. Feel free to ask questions as you proceed. Also, if you need books, try library genesis (type it on google). It will you give an access to books you would like to download. ( For example; Transonic Flow (its a book) ) If you would like to get into turbulence,, try Davidsons Turbulence: An Intro to... And so on. TGW likes this.

September 9, 2020, 08:10		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	That is an incredibly open ended question and one that probably doesn't have a simple answer. The 'best' mesh solution really depends on what you are trying to get our of your model. What does 'best' even mean? Most accurate? Fewest cells? I suggest that you try and frame the problem a little better.

September 10, 2020, 08:31		#4
cwl Senior Member Chaotic Water Join Date: Jul 2012 Location: Elgrin Fau Posts: 436 Rep Power: 17	If your professor doesn't provide you with books or references .. why would you need such professor %> PS Correct word is "mesh", not "net".

September 14, 2020, 13:35		#6
Karen Martirosyan New Member Deutschland Join Date: Sep 2020 Posts: 11 Rep Power: 5	Thank you soooo much my friend.It was really helpfull .I found what i needed.