results

Simulation Results Reel-Out testing at Maasvlakte, NL

Reel-out video — click to play

Overview of reel-out runs per wind speed

The test scenario:

The initial tether length is 150 m, the final length 380 m. The wind speed is the ground wind speed, measured at a height of 6 m, using a vertical wind profile law combining the exponential and logarithmic laws, matched to measurements at a near-shore site in Maasvlakte, NL. A ground-station with 20 kW nominal power and 30 kW peak power is assumed. The nominal reel-out speed is 3.5 m/s, the maximum force 8400 N.

datetimev_windpower_ratiototal_timert_factoropt_requestsopts_installedav_powermin_powermax_powermin_forceav_forcemax_forcev_ro_minv_ro_avv_ro_maxav_depowersuccess_criteria
2026-08-3013:08:103.51.11286.74.125588716193858783714920.021.031.40.288all 10 passed
2026-08-3009:20:0940.99281.23.95551562322627886119317570.031.291.570.282all 10 passed
2026-08-3011:49:1851.02236.13.685538367247941392208331110.041.842.210.274all 10 passed
2026-08-3011:36:3461.0171.93.4933732613185932212322945200.052.272.580.269all 10 passed
2026-08-3013:29:3371170.23.274412201241146013278454757290.072.683.110.266all 10 passed
2026-08-3013:37:2780.9964.33.433318563351224444586598070360.083.13.470.265all 10 passed
2026-08-3013:39:5990.9147.95.243322071395289095034665983580.083.33.590.274all 10 passed
2026-08-3013:42:48100.8254.74.624420329478249185024650276340.083.123.440.299all 10 passed
2026-08-3013:48:00110.8360.94.813318888479244494400606575060.073.113.370.312all 10 passed

Click on one of the labels to show an additional column group, ctrl+click to deselect, shift+click for multi-select.

The average mechanical power during reel-out, the force, and the speed are shown in the following plot. At about 9 m/s the maximal force of 8400 N is reached. From this wind speed onwards the force is limited by increasing the depower settings.

power curve

The optimal trajectory of the kite, the shape of the figure of eight, depends on the tether length and on the wind speed. Below, use the slider to adjust the ground wind speed, and see the shape of the desired and actual trajectory the kite flies. For each figure-of-eight, the AWETrim quasi-static optimizer calculated the optimal trajectory.

flight pattern, 3 m/s flight pattern, 4 m/s flight pattern, 5 m/s flight pattern, 6 m/s flight pattern, 7 m/s flight pattern, 8 m/s flight pattern, 9 m/s flight pattern, 10 m/s flight pattern, 11 m/s

The time series below show, for the same wind speed selected above, the cross-track error, elevation, course/heading tracking, steering, tether force and length, reel-out speed, depower, and the entry state machine over the whole run. The first subplot, `d ', shows the distance between the actual and planned trajectory in degrees.

time series, 3 m/s time series, 4 m/s time series, 5 m/s time series, 6 m/s time series, 7 m/s time series, 8 m/s time series, 9 m/s time series, 10 m/s time series, 11 m/s

The plots below show, for the same wind speed selected above, the tether force, reel-out speed and mechanical power over the whole run, and the cumulative mechanical energy.

power, 3 m/s power, 4 m/s power, 5 m/s power, 6 m/s power, 7 m/s power, 8 m/s power, 9 m/s power, 10 m/s power, 11 m/s

The plots below show, for the same wind speed selected above, the angle of attack (at the wing centre and the span mean), the wing and effective lift-to-drag ratio, and the apparent wind and kite speed over the whole run.

aerodynamics, 3 m/s aerodynamics, 4 m/s aerodynamics, 5 m/s aerodynamics, 6 m/s aerodynamics, 7 m/s aerodynamics, 8 m/s aerodynamics, 9 m/s aerodynamics, 10 m/s aerodynamics, 11 m/s

Acknowledgements

This work has been supported by the MERIDIONAL project, which receives funding from the European Union’s Horizon Europe Program under the grant agreement no. 101084216. The opinions expressed in this document reflect only the author’s view and reflects in no way the European Commission’s opinions. The European Commission is not responsible for any use that may be made of the information it contains.

These results were achieved using the following research software: