Comparison of vortex generators effect on shock wave induced separation

Flaszyński, Paweł

doi:10.2514/6.2016-3769

Cited by 4 publications

(3 citation statements)

References 14 publications

(14 reference statements)

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“…In early 2010s, the patent of rod VG (RVG) was proposed by Doerffer et al (2011). Examples of RVGs application, as a device used for flow control in subsonic and transonic flows, have been already presented by Flaszyński et al (2016), Tejero (2015) and Suarez et al (2016), i.e. helicopter rotor blades or wind turbine blades.…”

Section: Introductionmentioning

confidence: 99%

Source term model for rod vortex generator

Kwiatkowski

Flaszyński

Żółtak

2019

AEAT

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Purpose The simulations of grid-resolved rod vortex generators (RVGs) require high computational cost and time. Additionally, the computational mesh topology must be adjusted to rods geometries. The purpose of this study is to propose the new source term model for RVG. Design/methodology/approach The model was proposed by modification of Bender, Anderson, Yagle (BAY) model used to predict flows around different type of vortex generators (VGs) – vanes. Original BAY model was built on lifting line theory. The proposed model was implemented in ANSYS Fluent by means of the user-defined function technique. Additional momentum and energy sources are imposed to transport equations. Findings The computational results of source term model were validated against experimental data and numerical simulation results for grid-resolved rod. It was shown that modified BAY model can be successfully used for RVG in complex cases. An example of BAY model application for RVG on transonic V2C airfoil with strongly oscillating shock waves is presented. Aerodynamic performance predicted numerically by means of both approaches (grid resolved RVG and modeled) is in good agreement, what indicates application opportunity of the proposed model to complex cases. Practical implications Modified BAY model can be used to simulate the influence of RVGs in complex real cases. It allows for time/cost reduction if the location or distribution of RVG has to be optimized on a profile, wing or in the channel. Originality/value In the paper, the new modification of BAY model was proposed to simulate RVGs. The presented results are innovative because of original approach to model RVGs.

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Section: Introductionmentioning

confidence: 99%

Source term model for rod vortex generator

Kwiatkowski

Flaszyński

Żółtak

2019

AEAT

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“…In this paper, a new type of streamwise VG known as rod vortex generator (RVG) is proposed. The authors' previous experience on passive AJVGs led to the idea of introducing a rod instead of a jet. Similar to VVG or AJVG, an RVG creates a stable streamwise vortex as the effect of the interaction of boundary layer and inclined rod .…”

Section: Introductionmentioning

confidence: 99%

Application of rod vortex generators for flow separation reduction on wind turbine rotor

2018

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This paper focuses on flow control on wind turbine blades. A rod vortex generator (RVG) is proposed. Previous experimental and numerical results obtained for channels and blade sections proved RVGs to effectively enhance the streamwise shear stresses and reduce flow separation. The benefits of application of RVGs to control and decrease the flow separation on horizontal axis wind turbine rotor blades are assessed and presented in the paper. The numerical investigation was conducted with the FINE/Turbo solver from Numeca International, which solves the 3D Reynoldsaveraged Navier-Stokes equations. The validation of the numerical model for the clean case is based on phase VI of the Unsteady Aerodynamics Experiment. At selected operating conditions, flow control devices have proven to reattach the flow locally to the wall and improve the aerodynamic performance of the wind turbine. Additionally, the local implementation of RVGs shows strong effect on flow structure and interaction with the main flow to create a "shielding" effect, preventing further penetration of separation towards blade tip. As a consequence, the positive effect of RVGs exists outside the blade span covered by devices. The obtained aerodynamic improvement shows that RVGs may be used as an alternative to traditional flow control devices applied on wind energy turbines. KEYWORDS flow control, flow separation, NREL phase VI, vortex generator, wind energy 1 | INTRODUCTIONSince the industrial revolution, the world demand for energy has grown at a much faster rate than in all previous human history. As a consequence, man's dependency on fossil fuels and green house gasses emissions has risen ever since. In this context, wind energy is seen as one of the most promising solutions to man's ever-increasing demands of a clean source of energy. 1 The main drawback of wind energy compared with nonrenewable energy sources is the cost of energy (COE). The COE may be reduced by increasing the annual energy production (AEP) or decreasing the operation and maintenance cost. This increase of AEP may be achieved through higher availability of the system, thereby reducing the downtime.Nevertheless, the average availability of the onshore horizontal axis wind turbines ranges from 96% to 99%, which indicates slight scope for improvement. 2 The AEP may be also enhanced by increasing wind turbine and rotor sizes. A larger turbine can capture more energy through its lifetime, decreasing the relative COE per megawatt. The last decades development in the material science, control, and aerodynamics have allowed this growth of wind turbines sizes and a continuous reduction in COE. 3 At the end of 1989, a 300-kW wind turbine with 30-m rotor diameter was state of the art; nowadays, turbines with rotor diameters of up to 160 m (Vestas V164-8MW or V164-9.5MW) have been developed, and the current trend of increasing sizes is expected to continue in the future. 4,5 Presence of flow separation on wind turbine blades leads to increased aerodynamic losses, noise generation, and fatigue ...

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“…Several experimental investigations were conducted proving that RVGs and AJVGs can generate similar flow structures (Flaszynski et al, 2016). The potential application of the RVGs concerns external flows (e.g.…”

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confidence: 99%

Passive flow control application for rotorcraft in transonic conditions

Tejero

Doerffer

Flaszyński

et al. 2018

HFF

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Purpose Helicopter rotor blades are usually aerodynamically limited by the severe conditions present in every revolution: strong shock wave boundary layer interaction on the advancing side and dynamic stall on the retreating side. Therefore, different flow control strategies might be applied to improve the aerodynamic performance. Design/methodology/approach The present research is focussed on the application of passive rod vortex generators (RVGs) to control the flow separation induced by strong shock waves on helicopter rotor blades. The formation and development in time of the streamwise vortices are also investigated for a channel flow. Findings The proposed RVGs are able to generate streamwise vortices as strong as the well-known air-jet vortex generators. It has been demonstrated a faster vortex formation for the rod type. Therefore, this flow control device is preferred for applications in which a quick vortex formation is required. Besides, RVGs were implemented on helicopters rotor blades improving their aerodynamic performance (ratio thrust/power consumption). Originality/value A new type of vortex generator (rod) has been investigated in several configurations (channel flow and rotor blades).

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Comparison of vortex generators effect on shock wave induced separation

Cited by 4 publications

References 14 publications

Source term model for rod vortex generator

Source term model for rod vortex generator

Application of rod vortex generators for flow separation reduction on wind turbine rotor

Passive flow control application for rotorcraft in transonic conditions

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