GAMM2025

Session

S13: Flow control

S13

10 Apr 2025, 16:30

Lecture and Conference Centre

Conveners

S13: Flow control: S13.01

• Pawel Flaszyński
• Philipp Schlatter

S13: Flow control: S13.02

• Witold Elsner
• Philipp Schlatter

Description

Many technical applications involving flows profit from trying to manipulate the boundary conditions or flow parameters in such a way as to generate a desired effect, like reduced drag, increased mixing, attenuated or increased turbulence or reduced sound emission, for example. The sophistication of the governing equations requires a broad range of research topics and methods to be covered, including analytical treatments, reduced-order modelling, passive manipulation of boundaries in experiments involving riblets, active manipulations using actuators, for example, or numerical approaches involving the adjoint equations, amongst others. The speakers of our session reflect the broad application area of flow control and discuss difficulties in the application side and recent advances in the analysis, as well as experimental and numerical approaches.

296. Turbulent drag reduction: what we do know, and what we don’t

Davide Gatti

10/04/2025, 16:30

Most flows of industrial and technical relevance are turbulent. Turbulent flows typically exhibit larger viscous drag compared to an equivalent laminar flow. This fact prompted numerous efforts in reducing such excess drag – the so-called turbulent drag – during the last decades, enticed by potentially huge economic and environmental benefits. The challenges range from discovering efficient...

297. Spanwise wall oscillations without walls: a means to assess the physics of drag reduction

Karl Vieths

10/04/2025, 17:10

The reduction of skin friction drag in turbulent flows has constituted a significant field of research over the past few decades. Spanwise forcing represents one of the most extensively studied techniques for the reduction of turbulent drag. It entails the imposition of a spanwise oscillation of the wall in a turbulent wall bounded flow. Different studies (e.g., Quadrio & Ricco 2004) have...

298. Reinforcement learning for the identification of an active separation control strategy of a fully-turbulent wind tunnel flow

Ben Steinfurth

10/04/2025, 17:30

The pulsed ejection of air into a boundary layer represents an effective method to prevent or delay its separation from the surface. Despite many successful demonstrations, this approach has not reached a breakthrough in the aviation industry, which is arguably due to an excessive energy consumption.

Recent progress in the field of Deep Learning suggests that artificial neural networks can...

299. Turbulent separation control on an airfoil-type surface using spanwise corrugation

Piotr Kaminski

10/04/2025, 17:50

This study investigates the effects of two-dimensional streamwise wall waviness (WW) on turbulent boundary layer (TBL) separation over a NACA 4412 airfoil surface under adverse pressure gradient conditions. Both regular sinusoidal and tilted WW configurations are analyzed to determine their effectiveness in delaying flow separation. The universality of the optimal WW design is evaluated across...

300. Thermo-electro Hydrodynamic Instability in Microgravity Conditions: Experimental Investigations

Yaraslau Sliavin

10/04/2025, 18:10

The effect of the dielectrophoretic forces in convective flows under microgravity conditions were experimentally investigated to examine the onset and behavior of the hydrodynamic instability. A dielectric fluid confined within a differentially heated, vertically aligned cylindrical annulus was subjected to an alternating electric field at a frequency of 200 Hz during sounding rocket flight,...

301. Control effectiveness of vortex generators in high-speed flows in off-design conditions

Anne-Marie Schreyer

11/04/2025, 08:30

In aerospace transportation and propulsion systems, shock-induced flow separation leads to highly unsteady flow fields and has strong detrimental effects on the aerodynamic behavior and performance. To alleviate these effects, separation control is investigated and developed. A commonly pursued approach uses vortex generators of different design to increase the momentum transfer within the...

302. Aeroacoustic Effects of Rod Vortex Generators for the Reduction of Boundary Layer Separation

Pawel Flaszyński

11/04/2025, 09:10

Various industries such as urban air mobility, wind energy, aerospace, transportation, etc. have been imposed with noise emission regulations by most governments. This has led to an increase in research about noise emission and mitigation strategies. Specifically for the wind industry, larger turbine rotors implemented to increase energy production are also emitting higher sound levels which...

303. Silent conditions testing of pulsed jet actuator for separation flow control over large aerodynamic surface

Wit Stryczniewicz

11/04/2025, 09:30

Installation of Ultra High Bypass Ratio (UHBR) turbofan engines on airframes brings significant reductions of fuel consumption and emissions. However, due to limited height of the undercarriage, UHBR engines must mounted close to wing. This results in slat cut outs at the juncture of the engine pylon, which significantly promotes separation at high angles of attack. The flow separation in this...

304. Performance Enhancement of Small-Scale Wind Turbine using Response Surface Optimization Method

Roudouane Laouar

11/04/2025, 09:50

CANCELLED
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The performance of a wind turbine rotor depends on the wind characteristics of the site and the aerodynamic shape of the blades. The blade geometry determines the torque and the power generated by the rotor. This study investigates the enhancement of small Horizontal Axis Wind Turbine (HAWT) rotor performance by using Response Surface Methodology (RSM) through Computational...

305. Improving Small HAWT Rotor Performance through the Integration of MOGA and Screening Methods

Riyadh Bekkai

This study introduces an innovative methodology for enhancing the performance of wind turbines by optimizing the distribution of chord length and twist angle. The approach integrates a multi-objective genetic algorithm (MOGA) with a screening method, iteratively refining design candidates through a series of optimization cycles. These candidates are subsequently evaluated within a Design of...