What kind of fan is best for a DIY windtunnel?

[puedpued]

Hi guys,
I am really new to the concept of aerodynamics and really need some guidance for my university project.
First of all, I am going to make a DIY windtunnel based on this project http://www.instructables.com/id/DIY-Wind-Tunnel-20-Project-Paperclip/

The size of the testing section needs to be 60cm x 60cm (or 24" x 24"). I am aiming to achieve a windspeed approximately at 10-20 m/s. So my question is what kind of fan do I need? Would I need some thing like an industrial fan such as this: http://www.bunnings.com.au/dynabreeze-60cm-blue-industrial-drum-fan_p4440780

Or should i make some thing like this so I can control the fan speed with PWM :
http://www.instructables.com/id/PC-Box-Fan/

So for a 120mm fan, the flow rate is usually between 50~75 CFM. I have no idea how to convert this to m/s and if I use 25 fans, would this mean I just need to add the CFM together?

I am afraid that the industrial maybe too strong and the PC fan box may not be strong enough. Please give me some guidance.

Thank you for your time and help :)

 

[Nidum]

You really need to learn at least some basic fluid mechanics before starting this project .

To start you off though :

Volume flow through a hole is (air velocity) * (cross sectional area) - just for rough sums anyway .

Detailed calculation is a bit more complicated but not nescessary for your purpose .

Work in consistent units .

 

[berkeman]

Hi guys,
I am really new to the concept of aerodynamics and really need some guidance for my university project.
First of all, I am going to make a DIY windtunnel based on this project http://www.instructables.com/id/DIY-Wind-Tunnel-20-Project-Paperclip/

The size of the testing section needs to be 60cm x 60cm (or 24" x 24"). I am aiming to achieve a windspeed approximately at 10-20 m/s. So my question is what kind of fan do I need? Would I need some thing like an industrial fan such as this: http://www.bunnings.com.au/dynabreeze-60cm-blue-industrial-drum-fan_p4440780

Or should i make some thing like this so I can control the fan speed with PWM :
http://www.instructables.com/id/PC-Box-Fan/

So for a 120mm fan, the flow rate is usually between 50~75 CFM. I have no idea how to convert this to m/s and if I use 25 fans, would this mean I just need to add the CFM together?

I am afraid that the industrial maybe too strong and the PC fan box may not be strong enough. Please give me some guidance.

Thank you for your time and help :)

Welcome to the PF.

Here is a recent PF thread about wind tunnels -- it may help to give you some ideas and start to understand some of the calculations involved:

https://www.physicsforums.com/threads/wind-tunnel-help.817754/

 

[puedpued]

Thank you guys, I'll do more research :)