Wind Turbine Airfoil Performance at Different Blade Span Positions

Radius sets the section problem

The wind-turbine selection lesson listed the overall duties. This lesson is the spanwise change. Local blade speed is roughly ω times radius, plus the wind. A station at 20% of radius and a station at 90% do not share a Reynolds number, a Mach number or a structural thickness. Copying one polar along the blade is the mistake.

Three stations

What to store per station

1. Radius, chord, twist and the airfoil name.
2. Relative speed, Re and Mach at the design tip-speed ratio, and at a second ratio if the machine changes speed.
3. The polar used for the torque sum, with its method label, and the tripped polar used for the energy estimate you are willing to promise.
4. A note if the station is allowed to operate separated. A design that needs the root to be stalled should say so, and should not use an attached-flow CD there.

The blade is a stack of these records. Annual energy and noise are integrals over them. They are not properties of the mid-span DAT file alone.

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Where this sits in the series

In simple words: what this page is for

Root, mid-span and tip are different airfoils at different Reynolds numbers. The rotor works only if each station is analysed at its own speed, chord and thickness.

This lesson exists because section decisions fail when geometry, method labels and selection reasons are scattered. Wind Turbine Airfoil Performance at Different Blade Span Positions helps you keep a clean trail from shape to polar to choice.

Why the topic matters

Engineers lose time when a title sounds clear but the page only sketches the idea. This article expands Wind Turbine Airfoil Performance at Different Blade Span Positions so you can answer three questions without jargon: what is the idea, when do you use it, and how do you check it in a HENDOI product.

Read the sections above for the core definitions. Use the steps below to move from reading into a real project trail you can share with a teammate.

How to apply this in HENDOI

In practice: create a HENDOI account or log in, open HENFOIL, bring a section in (create, import DAT, or digitize), pass the geometry gate, climb the analysis ladder only as far as the decision needs, then compare and archive. Every calculated number should keep its method label.

When the section choice is ready for the aircraft, continue in HENSYNTH for mission, compliance and trades. Same account. Same plans.

What this page will not claim: a teaching polar or geometry note is not a flight-Re certificate. HENFOIL labels methods so you know what you bought. Tunnel data and professional judgement still sit outside any single software run.

Checklist before you leave this page

• Can you state the idea of Wind Turbine Airfoil Performance at Different Blade Span Positions in one sentence?
• Do you know which product owns the next action — HENFOIL or HENSYNTH?
• Will every number you keep carry a method label or a stored-run source?
• If you are new here, have you opened Register or Login?

Related reading on this site

• Airfoil Performance in Crosswind and Yawed Flow: What Engineers Should Know
• How to Evaluate Airfoils for Wind Tunnel Testing and Experimental Validation
• How to Measure Airfoil Lift and Drag in a Wind Tunnel
• Airfoil Wind Tunnel Testing: Instrumentation, Test Conditions and Data Reduction
• All HENDOI blog articles
• HENFOIL product page
• HENSYNTH product page
• Pricing — Student, Professional & Team
• FAQ
• Login · Register now

• Previous: Airfoils for human-powered aircraft
• Next: Airfoils for small electric propeller aircraft
• Index: all HENFOIL airfoil lessons

These pages teach the ideas. They are not wind-tunnel data and not a certification analysis. When a number matters, compute it at a stated Reynolds number, Mach number and transition setting, and keep the method label on the result. In HENFOIL that production polar is a VIC polar — see the analysis ladder and the polar field guide.