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Questions tagged [wind-tunnels]

13 questions
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How are wind tunnel models used when designing supersonic aircraft?

There are two things involved: wave drag and boundary layer separation. The wave drag depends on the Mach number while the latter depends on the Reynolds number of the flow. It's easy to maintain the incoming Mach number as it is independent of the…
Subodh
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Efficient 3D mesh topology for CFD simulation of turbine blade

I´m developing a tool to generate an openFoam wind tunnel case of a wind turbine. I already have the blade geometry constructed, but I'm really new to CFD and parametric meshing. I found some articles where they mention a C topology to mesh the…
efirvida
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3
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What is the power and max flow rate required to rotate a 300 W wind turbine?

I have purchased a wind turbine with a power of 300 W, the start up wind speed is 2.5 m/s, rated wind speed is 11 m/s, and the survival wind speed is 45 m/s, and what I'm going to do is to make an educational modeling for how to generate electrical…
Mohamed AbdelAlim
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Angular Velocity of motor shaft as function of Angular Position

I have a set of shafts that need to be rotated at a high frequency (~1000 RPM) but not at a constant speed. That is to say, the angular velocity of the shaft needs to be a periodic function of the shaft's angular position. This bizarre predicament…
plam
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1
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1 answer

Reed played by the wind

I am trying to build a reed instrument played by the wind (kind of like these aeolian instruments: Eerie musical instruments played by the wind from around the world but using reeds rather than strings), but given the necessary pressure to make the…
ali
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0
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Centrifugal Compressor selection

I am currently trying to select a centrifugal compressor for a wind tunnel project. The requirement is that the flow velocity in the test section is Ma 0.1. The geometry of the wind tunnel has already been defined, so all the dimensions of the…
aziz
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Why are there two fans in open circuit wind tunnel in laboratory?

In an experiment in hydraulics lab of my college, very recently someone asked me, why were there two fans in the open circuit wind tunnel. That wind tunnel is used for conducting experiment for finding boundary layer thickness over a flat…
hkishnani3
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Why would experimental Mach #s in a wind tunnel be higher that Mach #s predicted by theory (inviscid) for the same nozzle geometry

The figure below shows the mach numbers across a supersonice convergent-divergent nozzle. Since the experimental Mach numbers (calculated from measured pressures along the walls of the nozzle) take into account viscous forces, shouldnt their mach…
Fellow learner
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How can we determine that the flow in a wind tunnel reaches the steady-state condition?

I am investigating the flow and heat transfer over a cylinder in a wind tunnel. I want to record the data that I need to calculate the flow characteristics, But how can I make sure that the steady-state condition is achieved? There are very small…
Alfred Johnson
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Wind behavior and pattern

From the 5 options, which one shows the worse wind effect? Is it (b) because wind speeds accelerate through a gap? But how about in comparison to (c)? Or (d) due to the height and sharp corners? If it's (b), does building shape matter? Meaning, what…
SSan
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sudden expansion in wind tunnel diffuser design

I have a question regarding my wind tunnel design. Originally the system had a 90mm dc fan pulling air, upon testing I find the design unsatisfactory as air movement was very "weak" ( I used my hand to feel the air moving at the front end ). So I…
Kevin Nan Woon Kai
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How to do Blade Element Momentum Theory Analysis for NACA airfoils?

I wanna perform BEMT analysis on blades of different geometry and not just symmetric thin airfoil. How to do this?
Adithya NYY
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Windproof open doors room design

I live somewhere where it's relatively warm the entire year (around 10ºC is the coldest you'll get in some days during a normal winter). I am dreaming of a house design that I intend to build in the near to mid-term future. I have dogs and I want…
Bruno Finger
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