Wake Loss Calculator

Model wake deficits from turbines across your corridor. Tune decay, thrust, and overlap factors easily. See power loss, energy impact, and spacing guidance instantly.

Downloads
Run a calculation to enable CSV and PDF exports.
Typical range: 3 to 15 m/s.
Used to scale wake expansion with distance.
Distance from upstream turbine to target turbine.
Common range: 0.6 to 0.9.
Number of contributing wakes in the sector.
0 means no overlap, 1 means full overlap.
Higher turbulence usually speeds wake recovery.
Auto applies a simple TI-based estimate.
Typical onshore values: 0.04–0.075.
Optional: used to estimate wake power.
Optional: used to estimate annual energy loss.
Applied only to estimated wake power.
Reset

This calculator provides a planning-grade estimate for layout comparison.

Example data table

Scenario Wind (m/s) D (m) x (m) Ct TI (%) Upstream Overlap Wake loss (%)
Baseline spacing 9.0 120 600 0.80 10 2 0.85 ≈ 13–18
Wider spacing 9.0 120 900 0.80 10 2 0.85 ≈ 7–11
Higher turbulence 9.0 120 600 0.80 16 2 0.85 ≈ 10–15
Values shown are indicative. Actual results depend on terrain, stability, and turbine controls.

Formula used

This tool uses a planning-grade Jensen/Park wake model for velocity deficit and a V³ power scaling approximation.

For detailed design, confirm results with site-specific flow modeling and measured power curves.

How to use this calculator

  1. Enter the free-stream wind speed for the selected direction sector.
  2. Set rotor diameter and downstream distance between turbines.
  3. Choose Ct and the number of upstream turbines affecting the target.
  4. Use overlap to represent partial wake coverage at the rotor.
  5. Keep k on Auto unless you have a calibrated wake decay value.
  6. Optional: add baseline power and AEP to estimate losses.
  7. Press Calculate, then download CSV or PDF if needed.

Wake losses in layout planning

Wake losses reduce effective wind speed reaching downstream machines, lowering energy yield. During early layout work, you can compare spacing options, turbine counts per string, and directional sectors without running heavy simulations. Use consistent input assumptions across scenarios so relative differences remain meaningful for design decisions.

Key inputs that influence recovery

Downstream distance and rotor diameter set the geometric scale of wake expansion. Thrust coefficient represents how strongly the rotor extracts momentum, which increases the initial deficit. Ambient turbulence and the wake decay factor govern mixing and recovery; higher turbulence generally shortens the wake. The overlap factor lets you represent partial rotor coverage when wakes are offset.

Interpreting velocity deficit results

The calculator reports a combined velocity deficit from one or more upstream turbines. A deficit of 10% means the downstream wind speed is 90% of free flow for the selected sector. Because the relationship is nonlinear, small changes in deficit can create larger changes in power. Review deficit together with wake radius to understand how quickly the wake spreads.

Converting wind speed change to power loss

For planning estimates, power is approximated to scale with the cube of wind speed. If wake speed is 95% of free flow, the power ratio is about 0.95³, or 0.86, which corresponds to roughly 14% loss in that operating region. If you enter baseline power or annual energy, the tool converts ratios into kW and MWh impacts. When testing alternatives, keep wind speed and Ct aligned with the turbine’s rated region. Use sector-specific distances if the row is angled. For complex terrain, treat the output as screening only and flag cases where deficit remains high beyond 8–10 rotor diameters. Also record availability and curtailment assumptions so stakeholders do not confuse wake loss with planned downtime.

Using results for construction coordination

Wake studies support corridor alignment, crane pad placement, and access planning by indicating which turbines are most sensitive to upstream interference. When sequencing foundations or commissioning, prioritize measurement and tuning on strings with higher predicted losses. Document the sector assumptions, then re-check outputs after changing hub height, rotor size, or spacing.

FAQs

What does the overlap factor represent?

It represents how much of the downstream rotor is covered by the wake. Use 1.0 for full coverage, or lower values when wakes are offset or partially intersect the rotor disk.

Should I use Auto or Manual wake decay k?

Use Auto for screening when only turbulence intensity is known. Use Manual when you have site-calibrated values from measurements, CFD studies, or validated energy assessment reports.

Why does a small deficit cause a large power loss?

In the sub-rated region, turbine power rises roughly with wind speed cubed. A few percent reduction in speed can translate into a noticeably larger reduction in power and energy.

Can I model different wind directions with this tool?

Yes. Run separate scenarios for each direction sector, updating downstream distance, turbine count, and overlap based on the alignment of rows and the wind rose for your site.

How accurate are the results for complex terrain?

This is a planning-grade model intended for comparisons. In complex terrain or stable atmospheric conditions, use higher-fidelity flow modeling and validate with site measurements.

How do the optional baseline fields help?

Baseline power converts the ratio into expected kW under free flow, adjusted by availability. Baseline AEP converts the loss percentage into an estimated annual energy loss in MWh.

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