the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 09 Feb 2023
Aerodynamic simulation of rough and eroded blades, AEP effect and mitigation using low drag vortex generators
Abstract. Blade roughness depositions or blade erosion have an unquestionably effect over blade aerodynamics and wind turbine power production. This work is focused on the simulation using Computational Fluid Dynamics (CFD) of the NACA 633418 airfoil with high roughness values and with different erosion typologies (pits and extreme losses of material). The CFD code used is OpenFOAM v8 and different technologies are selected to create the meshes to capture properly geometries' defects (ICEMCFD and ANSYS Workbench).
This study goes a step further by using low drag Vortex Generators (VGs) to mitigate the roughness and erosion harmful effects. Low drag VGs are compared with conventional ones and afterwards 3D blade sections are computed with roughness and erosion incorporating low drag VGs to evaluate the blade performance recovery achieved by the use of VGs. Finally, the impact of the different configurations (rough, eroded, rough + VG and eroded + VG) over Annual Energy Production (AEP) is evaluated on a virtual 2.5 MW wind turbine. The most important finding of the work presented in this paper is that AEP losses due to the existence of blade surface roughness or erosion can be recovered from the use of VGs up to 1.5 %.
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CC1: 'Comment on wes-2023-8', Kisorthman Vimalakanthan, 23 Mar 2023
Dear author,
I appreciate the high quality of the work, but I would like to suggest a few changes in order to further enhance the content.
- Could you please provide a glossary of terms, symbols and include definitions for acronyms or abbreviations used throughout the paper
- On page 3, line 73 –Any reference to support your statement: “More recently vortex generators are being included in the tip area of the blades to improve efficiency in rough or eroded conditions.”
- On page 4, line 102 –Please include the chord length of the airfoil
- On page 4, line 108 – What value of Ncrit was used for the eN transition method? Please include in text
- On page 4, line 109 – The CFD model setup description is insufficient, could you please provide more information on convergence criteria, boundary conditions, force and residual history plot? and the order of models and solvers used for the computation. Please specify the residual drop, i.e. by how many orders of magnitude the residuals dropped for all equations. This is important if the order of magnitude of initial residuals is not 1 for all PDEs (i.e. are these residuals normalized?).
- On page 4, line 113 – What relationship was used to determine the equivalent sand grain value, please provide a reference
- Page 5, line 121 – Please provides some images of the difference between the (S-M) and (U-M) grids
- Page 15, Figure 13 – Please include the chord location of the VGs in the caption
- Page 15, Line 194 - Please provide a table with the dimensional information of the different VGs, such as the vane angle, the lateral distance between the vanes and height with respect to the chord and/or local boundary layer thickness
- Page 15, Line 195 – What was the metric used to determine the best VG location along the airfoil chord, please provide the results from the parametric study.
- Page 21, Line 225 – Please provide more detail about the AEP model, was it via BEM calculations? was drag contribution added to the induction calculation? Which wind distribution was considered, and which mean windspeed was used?
Overall, the quality of the paper is impressive as it contains abundant information and validation, ranging from the CFD-modelled roughness to the AEP impact.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2023-8-CC1 - AC1: 'Reply on CC1', Beatriz Mendez, 18 Apr 2023
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RC1: 'Comment on wes-2023-8', Anonymous Referee #1, 24 Mar 2023
Review on the manuscript entitled “Aerodynamic simulation of rough and eroded blades, AEP effect and mitigation using low drag vortex generators” by Bretos-Arguiñena and Méndez-López (wes-2023-8)
The manuscript presents a study on the effect of surface roughness and erosion on an airfoil and wind turbine blades using CFD computations, and a mitigation strategy on reducing the effect by using vortex generators. The study is interesting and can help the wind energy community to solve the roughness and erosion problems on wind turbine blades in reality. However, the paper is not well written and difficult to read as it contains many typo errors and misses important details and descriptions on the used models and also misses references. The authors are suggested to revise their manuscript before acceptance.
Detailed comments:
- The novelty of the paper should be listed.
- You need to cite references for your statements in the introduction. Your discussion in the introduction goes too fast to 2D quantification. A general discussion about blade roughness and erosion for wind turbine blades is interesting.
- “moving upwards”: what direction is upwards?
- Line 28: What is “non specified airfoil”?
- Line 103: What turbulence model is “the turbulence model”?
- Section 2.1: What is k-k1-w transition model? A short description with reference is required. Same comment for the transition model of eN.
- Line 113: When you use a wall model for the rough surface part, what wall boundary condition do you use for the rest part of surface? Do you use a similar mesh resolution for both parts?
- The stall part of the lift and drag forces is not captured. Any suggestion for improvement?
- In the rough cases, what turbulence model did you use?
- In the erosion cases, you need to make a mesh sensitivity study as the small erosion parts are not easy to be captured as there are no measurement data to compare with.
- Many captions are miss-leading. For example, in Figure 8, in the first two cases it is indicated with the turbulence model, but not in the other cases.
- Section 4 on AEP is extremely short. Some details about the code and blades are required. What wind conditions do you consider? How do you use the 2D CFD results for rotor computations? Any corrections were performed?
Citation: https://doi.org/10.5194/wes-2023-8-RC1 - AC2: 'Reply on RC1', Beatriz Mendez, 18 Apr 2023
-
RC2: 'Comment on wes-2023-8', Anonymous Referee #2, 06 Apr 2023
- AC3: 'Reply on RC2', Beatriz Mendez, 08 May 2023
Status: closed
-
CC1: 'Comment on wes-2023-8', Kisorthman Vimalakanthan, 23 Mar 2023
Dear author,
I appreciate the high quality of the work, but I would like to suggest a few changes in order to further enhance the content.
- Could you please provide a glossary of terms, symbols and include definitions for acronyms or abbreviations used throughout the paper
- On page 3, line 73 –Any reference to support your statement: “More recently vortex generators are being included in the tip area of the blades to improve efficiency in rough or eroded conditions.”
- On page 4, line 102 –Please include the chord length of the airfoil
- On page 4, line 108 – What value of Ncrit was used for the eN transition method? Please include in text
- On page 4, line 109 – The CFD model setup description is insufficient, could you please provide more information on convergence criteria, boundary conditions, force and residual history plot? and the order of models and solvers used for the computation. Please specify the residual drop, i.e. by how many orders of magnitude the residuals dropped for all equations. This is important if the order of magnitude of initial residuals is not 1 for all PDEs (i.e. are these residuals normalized?).
- On page 4, line 113 – What relationship was used to determine the equivalent sand grain value, please provide a reference
- Page 5, line 121 – Please provides some images of the difference between the (S-M) and (U-M) grids
- Page 15, Figure 13 – Please include the chord location of the VGs in the caption
- Page 15, Line 194 - Please provide a table with the dimensional information of the different VGs, such as the vane angle, the lateral distance between the vanes and height with respect to the chord and/or local boundary layer thickness
- Page 15, Line 195 – What was the metric used to determine the best VG location along the airfoil chord, please provide the results from the parametric study.
- Page 21, Line 225 – Please provide more detail about the AEP model, was it via BEM calculations? was drag contribution added to the induction calculation? Which wind distribution was considered, and which mean windspeed was used?
Overall, the quality of the paper is impressive as it contains abundant information and validation, ranging from the CFD-modelled roughness to the AEP impact.
Disclaimer: this community comment is written by an individual and does not necessarily reflect the opinion of their employer.Citation: https://doi.org/10.5194/wes-2023-8-CC1 - AC1: 'Reply on CC1', Beatriz Mendez, 18 Apr 2023
-
RC1: 'Comment on wes-2023-8', Anonymous Referee #1, 24 Mar 2023
Review on the manuscript entitled “Aerodynamic simulation of rough and eroded blades, AEP effect and mitigation using low drag vortex generators” by Bretos-Arguiñena and Méndez-López (wes-2023-8)
The manuscript presents a study on the effect of surface roughness and erosion on an airfoil and wind turbine blades using CFD computations, and a mitigation strategy on reducing the effect by using vortex generators. The study is interesting and can help the wind energy community to solve the roughness and erosion problems on wind turbine blades in reality. However, the paper is not well written and difficult to read as it contains many typo errors and misses important details and descriptions on the used models and also misses references. The authors are suggested to revise their manuscript before acceptance.
Detailed comments:
- The novelty of the paper should be listed.
- You need to cite references for your statements in the introduction. Your discussion in the introduction goes too fast to 2D quantification. A general discussion about blade roughness and erosion for wind turbine blades is interesting.
- “moving upwards”: what direction is upwards?
- Line 28: What is “non specified airfoil”?
- Line 103: What turbulence model is “the turbulence model”?
- Section 2.1: What is k-k1-w transition model? A short description with reference is required. Same comment for the transition model of eN.
- Line 113: When you use a wall model for the rough surface part, what wall boundary condition do you use for the rest part of surface? Do you use a similar mesh resolution for both parts?
- The stall part of the lift and drag forces is not captured. Any suggestion for improvement?
- In the rough cases, what turbulence model did you use?
- In the erosion cases, you need to make a mesh sensitivity study as the small erosion parts are not easy to be captured as there are no measurement data to compare with.
- Many captions are miss-leading. For example, in Figure 8, in the first two cases it is indicated with the turbulence model, but not in the other cases.
- Section 4 on AEP is extremely short. Some details about the code and blades are required. What wind conditions do you consider? How do you use the 2D CFD results for rotor computations? Any corrections were performed?
Citation: https://doi.org/10.5194/wes-2023-8-RC1 - AC2: 'Reply on RC1', Beatriz Mendez, 18 Apr 2023
-
RC2: 'Comment on wes-2023-8', Anonymous Referee #2, 06 Apr 2023
- AC3: 'Reply on RC2', Beatriz Mendez, 08 May 2023
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