Control of Unsteady Aerodynamic Loads Using Adaptive Blowing

Mueller-Vahl, Hanns; Nayeri, Christian Navid; Paschereit, Christian Oliver; Greenblatt, David

doi:10.2514/6.2014-2562

Cited by 7 publications

(3 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, load alleviation induced by a suction or pulsed-blowing coupled mechanism [266] is attributable to boundarylayer extraction (suction) and energizing (blowing), unsteady shear-layer excitation, thrust generation and streamwise vortices. Adaptive blowing (regulated steady blowing) was also credited with load-excursion elimination, by controlling boundary-layer separation using jet-momentum flux [267], with a successful demonstration of the eradication of dynamic-stall vortex using jet momentum under deep stall conditions. Next, dynamic blowing was also successfully applied for lift-excursions and dynamic-stall suppression, to achieve nearly constant phase-averaged lift or mitigated unsteady-aerodynamic loads [268], whereas passive adaptive blowing may be ideal for load alleviation and reduced blade-root bending and tip deflections [269]; mainly, this self-regulatory mechanism is governed by pressure-differential feedback obtained from control-ports on either side of the aerofoil/blade.…”

Section: Blowing-suction Controlmentioning

confidence: 99%

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Akhter

Omar

2021

Energies

View full text Add to dashboard Cite

It is projected that, in the following years, the wind‐energy industry will maintain its rapid growth over the last few decades. Such growth in the industry has been accompanied by the desirability and demand for larger wind turbines aimed at harnessing more power. However, the fact that massive turbine blades inherently experience increased fatigue and ultimate loads is no secret, which compromise their structural lifecycle. Accordingly, this demands higher overhaul‐and‐maintenance (O&M) costs, leading to higher cost of energy (COE). Introduction of flow‐control devices on the wind turbine is a plausible solution to this issue. Flow‐control mechanisms feature the ability to effectively enhance/suppress turbulence, advance/delay flow transition, and prevent/promote separation, leading to enhancement in aerodynamic and aeroacoustics performance, load alleviation and fluctuation suppression, and eventually wind turbine power augmentation. These flow‐control devices are operated primarily under two schemes: passive and active control. Development and optimization of flow‐control devices present the potential for reduction in the COE, which is a major challenge against traditional power sources. This review performs a comprehensive and up‐to‐date literature survey of selected flow‐control devices, from their time of development up to the present. It contains a discussion on the current prospects and challenges faced by these devices, along with a comparative analysis centered on their aerodynamic controllability. General considerations and conclusive remarks are presented after the discussion.

show abstract

Section: Blowing-suction Controlmentioning

confidence: 99%

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Akhter

Omar

2021

Energies

View full text Add to dashboard Cite

show abstract

“…The time delay became more significant with increasing angles of attack because of more separated flow. The effects of the slot blowing on unsteady aerodynamic load control with a freestream velocity from 6.7 m/s to 22.2 m/s on NACA0018 aerofoil was experimentally evaluated by Mueller-Vahl et al [94]. The results showed that the lift oscillation due to the unsteady incoming flow can be effectively counteracted by dynamically adapting the slot blowing velocity.…”

Section: Surface Jet Blowingmentioning

confidence: 99%

A Review of Flow Control for Gust Load Alleviation

Qin

2022

Applied Sciences

View full text Add to dashboard Cite

Effective control of aerodynamic loads, such as maneuvering load and gust load, allows for reduced structural weight and therefore greater aerodynamic efficiency. After a basic introduction in the types of gusts and the current gust load control strategies for aircraft, we outline the conventional gust load alleviation techniques using trailing-edge flaps and spoilers. As these devices also function as high-lift devices or inflight speed brakes, they are often too heavy for high-frequency activations such as control surfaces. Non-conventional active control devices via fluidic actuators have attracted some attention recently from researchers to explore more effective gust load alleviation techniques against traditional flaps for future aircraft design. Research progress of flow control using fluidic actuators, including surface jet blowing and circulation control (CC) for gust load alleviation, is reviewed in detail here. Their load control capabilities in terms of lift force modulations are outlined and compared. Also reviewed are the flow control performances of these fluidic actuators under gust conditions. Experiments and numerical efforts indicated that both CC and surface jet blowing demonstrate fast response characteristics, capable for timely adaptive gust load controls.

show abstract

“…Neunaber and Braud create an inversed EOG by rotating a bar into the inflow field of a wind tunnel 15 . Other two‐dimensional studies show load alleviation potential by active blowing 16 or trailing edge flaps, 17 yet they do not target extreme loads specifically.…”

Section: Introductionmentioning

confidence: 99%

Experimental assessment of a blended fatigue‐extreme controller employing trailing edge flaps

et al. 2022

Self Cite

View full text Add to dashboard Cite

This paper presents an experimental assessment of a blended fatigue‐extreme controller for load control employing trailing edge flaps on a lab‐scale wind turbine. The controller blends between a repetitive model predictive controller that targets fatigue loads and a dedicated extreme load controller, which consists of a simple on‐off load control strategy. The Fatigue controller uses the flapwise blade root bending moments of the three blades as input sensors. The Extreme controller additionally uses on‐blade angle of attack and velocity measurements as well as acceleration measurements to detect extreme events and to allow for a fast reaction. The experiments are conducted on the Berlin Research Turbine within the large wind tunnel of the TU Berlin. In order to reproduce test cases with deterministic extreme wind conditions that follow industry standards, the wind tunnel was redesigned. The analyzed test cases are extreme direction change, extreme coherent gust, extreme operating gust and extreme coherent gust with direction change. The test cases are analyzed by on‐blade angle of attack and velocity measurements. The load control performance of the Blended controller is compared to the pure fatigue oriented and the pure extreme load controller. The Blended controller achieves a maximum flapwise blade root bending moment reduction of 23%, which is comparable to the reduction achieved by the Extreme controller.

show abstract

Control of Unsteady Aerodynamic Loads Using Adaptive Blowing

Cited by 7 publications

References 38 publications

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

Review of Flow-Control Devices for Wind-Turbine Performance Enhancement

A Review of Flow Control for Gust Load Alleviation

Experimental assessment of a blended fatigue‐extreme controller employing trailing edge flaps

Contact Info

Product

Resources

About