the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 08 Jan 2025
Modelling the influence of streamwise flow field acceleration on the aerodynamic performance of an actuator disc
Abstract. In the present work, a simple model is derived for the situation of an actuator disc (AD) operating in a background flow field featuring a constant streamwise velocity gradient. Reynolds-averaged Navier-Stokes (RANS) simulations of this scenario are performed, showing that a positive acceleration yields a reduction of induction and vice versa, a negative acceleration leads to an increase of induction. The new model accurately captures this behavior and significantly reduces the prediction error compared to classical momentum theory, where the effect of the background flow acceleration is disregarded. The model indicates that the maximum power coefficient and the corresponding values of the optimal induction and thrust coefficient depend on the flow acceleration.
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Status: open (until 17 Feb 2025)
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RC1: 'Comment on wes-2024-181', Anonymous Referee #1, 23 Jan 2025
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The authors proposed a modification of the classical momentum theory to account for the effect of streamwise velocity gradients on the rotor induction and global performance. The reviewer believes the topic and activity are very interesting, innovative and worthy of investigation. The adopted methodology is adequate for the scope of the study and consistent throughout the work. Modelling assumptions and limitations are clearly stated and discussed. Nonetheless, the presentation of the work and the organization of the manuscript need improvement.
Some specific considerations:
- Abstract: although clearly stated in the rest of the paper, it would be more effective to also add to the abstract what is the field of application of this model (e.g., wind turbine in complex terrain);
-  Line 60: there is a typo, it should be: "U and u are the [...] velocities;
- The current organization of the manuscript can be improved for clarity: the description of the numerical model should be fully contained in Section 3, while a dedicated Section should be created for the validation part before the current Section 4. Figs. 3 and 4 should be moved to this new section, as they are currently too far from the part where they are commented;
- Figure 2: it would be nice to add a picture of the computational grid;
- Figures 2b, 3, 4, 5, and 6 all have formatting issues: missing decimal separators in the axis ticks, missing legend entries, missing axis labels and units. Please revise this figures carefully;
- Line 183: a practical definition of the length scale l is stated very late in the paper. It is recommended to already discuss this aspect in Section 2, where the model is presented.
The publication of the manuscript is recommended once the minor modifications described so far has been performed.Â
Citation: https://doi.org/10.5194/wes-2024-181-RC1
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Supplementary data for manuscript "Modelling the influence of streamwise flow field acceleration on the aerodynamic performance of an actuator disc" Clemens Paul Zengler https://doi.org/10.11583/DTU.27222912
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