Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine
Vertical Axis Wind Turbines (VAWTs) have proven to be suitable for changing wind conditions, particularly in urban settings. In this paper, a 2D URANS (Unsteady Reynolds-Averaged Navier Stokes) numerical analysis is employed for an H-Darrieus VAWT. A turbulent domain is created through systemically...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-02-01
|
| Series: | Energies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1073/16/5/2250 |
| _version_ | 1797615454208917504 |
|---|---|
| author | Lakshmi Srinivasan Nishanth Ram Sudharshan Bharatwaj Rengarajan Unnikrishnan Divakaran Akram Mohammad Ratna Kishore Velamati |
| author_facet | Lakshmi Srinivasan Nishanth Ram Sudharshan Bharatwaj Rengarajan Unnikrishnan Divakaran Akram Mohammad Ratna Kishore Velamati |
| author_sort | Lakshmi Srinivasan |
| collection | DOAJ |
| description | Vertical Axis Wind Turbines (VAWTs) have proven to be suitable for changing wind conditions, particularly in urban settings. In this paper, a 2D URANS (Unsteady Reynolds-Averaged Navier Stokes) numerical analysis is employed for an H-Darrieus VAWT. A turbulent domain is created through systemically randomising the inlet velocity to create macro-turbulence in front of the VAWT. The parameters for spatial and temporal randomisation of velocity and its effects on the turbine performance are studied for a mean free stream velocity, U<sub>∞</sub> = 10 m/s, and a tip speed ratio (TSR) of 4.1. The mean Coefficient of power (C<sub>p</sub>) for randomised fluctuation of 2 m/s and half-cycle randomisation update frequency is 0.411 and for uniform inlet velocity is 0.400. The C<sub>p</sub> vs. Tip Speed ratio plot suggests that the optimal tip speed ratio for operation is around 4.1 for this particular wind turbine of diameter 1 m, chord 0.06 m, and NACA 0018 airfoils. The effect of randomisation for tip speed ratio λ = 2.5, 3.3, 4.1, and 5.3 on the performance of the turbine is studied. Turbine wake recovers at a faster rate for macro-turbulent conditions and is symmetric when compared to wake generated by uniform velocity inlet. The maximum velocity deficit for a distance behind the turbine, x/d = 8 at TSR (λ) = 4.1 is 46% for randomised inlet and 64% for uniform inlet. The effect of randomisation for λ = 2.5 to 5.3 on the performance of the turbine is analysed. A time-varying gust based on International Electrotechnical Commission (IEC) Extreme Operating Gust is used to study the effect of fluctuating wind conditions in a turbulent environment. Since real-time conditions often exceed gust factors mentioned by IEC, winds with large gust factors such as 1.50, 1.64, and 1.80 are analysed. With an increase in gust amplitude, U<sub>gust</sub> = 6 m/s to U<sub>gust</sub> = 12 m/s on a free stream velocity of U∞ = 10 m/s, the mean C<sub>p</sub> decreases from 0.41 to 0.35 since the wind turbine operates under tip speed ratios outside optimal range due to large fluctuations in incoming velocity. |
| first_indexed | 2024-03-11T07:26:34Z |
| format | Article |
| id | doaj.art-7706153470b84d40b11153fe8e11e182 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-11T07:26:34Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-7706153470b84d40b11153fe8e11e1822023-11-17T07:36:09ZengMDPI AGEnergies1996-10732023-02-01165225010.3390/en16052250Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind TurbineLakshmi Srinivasan0Nishanth Ram1Sudharshan Bharatwaj Rengarajan2Unnikrishnan Divakaran3Akram Mohammad4Ratna Kishore Velamati5Department of Mechanical Engineering, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore 641112, IndiaDepartment of Mechanical Engineering, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore 641112, IndiaDepartment of Mechanical Engineering, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore 641112, IndiaDepartment of Mechanical Engineering, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore 641112, IndiaDepartment of Aerospace Engineering, King Abdulaziz University, Jeddah 21589, Saudi ArabiaDepartment of Mechanical Engineering, Amrita School of Engineering Coimbatore, Amrita Vishwa Vidyapeetham, Coimbatore 641112, IndiaVertical Axis Wind Turbines (VAWTs) have proven to be suitable for changing wind conditions, particularly in urban settings. In this paper, a 2D URANS (Unsteady Reynolds-Averaged Navier Stokes) numerical analysis is employed for an H-Darrieus VAWT. A turbulent domain is created through systemically randomising the inlet velocity to create macro-turbulence in front of the VAWT. The parameters for spatial and temporal randomisation of velocity and its effects on the turbine performance are studied for a mean free stream velocity, U<sub>∞</sub> = 10 m/s, and a tip speed ratio (TSR) of 4.1. The mean Coefficient of power (C<sub>p</sub>) for randomised fluctuation of 2 m/s and half-cycle randomisation update frequency is 0.411 and for uniform inlet velocity is 0.400. The C<sub>p</sub> vs. Tip Speed ratio plot suggests that the optimal tip speed ratio for operation is around 4.1 for this particular wind turbine of diameter 1 m, chord 0.06 m, and NACA 0018 airfoils. The effect of randomisation for tip speed ratio λ = 2.5, 3.3, 4.1, and 5.3 on the performance of the turbine is studied. Turbine wake recovers at a faster rate for macro-turbulent conditions and is symmetric when compared to wake generated by uniform velocity inlet. The maximum velocity deficit for a distance behind the turbine, x/d = 8 at TSR (λ) = 4.1 is 46% for randomised inlet and 64% for uniform inlet. The effect of randomisation for λ = 2.5 to 5.3 on the performance of the turbine is analysed. A time-varying gust based on International Electrotechnical Commission (IEC) Extreme Operating Gust is used to study the effect of fluctuating wind conditions in a turbulent environment. Since real-time conditions often exceed gust factors mentioned by IEC, winds with large gust factors such as 1.50, 1.64, and 1.80 are analysed. With an increase in gust amplitude, U<sub>gust</sub> = 6 m/s to U<sub>gust</sub> = 12 m/s on a free stream velocity of U∞ = 10 m/s, the mean C<sub>p</sub> decreases from 0.41 to 0.35 since the wind turbine operates under tip speed ratios outside optimal range due to large fluctuations in incoming velocity.https://www.mdpi.com/1996-1073/16/5/2250vertical axis wind turbinegustmacroturbulenceURANS |
| spellingShingle | Lakshmi Srinivasan Nishanth Ram Sudharshan Bharatwaj Rengarajan Unnikrishnan Divakaran Akram Mohammad Ratna Kishore Velamati Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine Energies vertical axis wind turbine gust macroturbulence URANS |
| title | Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine |
| title_full | Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine |
| title_fullStr | Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine |
| title_full_unstemmed | Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine |
| title_short | Effect of Macroscopic Turbulent Gust on the Aerodynamic Performance of Vertical Axis Wind Turbine |
| title_sort | effect of macroscopic turbulent gust on the aerodynamic performance of vertical axis wind turbine |
| topic | vertical axis wind turbine gust macroturbulence URANS |
| url | https://www.mdpi.com/1996-1073/16/5/2250 |
| work_keys_str_mv | AT lakshmisrinivasan effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine AT nishanthram effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine AT sudharshanbharatwajrengarajan effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine AT unnikrishnandivakaran effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine AT akrammohammad effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine AT ratnakishorevelamati effectofmacroscopicturbulentgustontheaerodynamicperformanceofverticalaxiswindturbine |