CFD-Based Control System for Gust Load Alleviation on a Two-Dimensional Aerofoil
Author
Titel, Manuel
Term
4. term
Education
Publication year
2024
Submitted on
2024-02-12
Pages
37
Abstract
Dette speciale undersøger, hvordan man kan mindske belastninger fra vindstød på en todimensionel vingekontur ved hjælp af en bagkantflap styret af et CFD-baseret system. Forfatteren udvikler en numerisk strømningsmodel i Ansys Fluent med Spalart–Allmaras turbulensmodellering med fokus på præcis forudsigelse af løftekraft. Modellen valideres mod tilgængelige forsøgsdata for overfladetryk og grænselagets hastighedsprofiler (Nakayama, 1985) og viser god overensstemmelse. Både vandrette og lodrette vindstød samt forskellige flapafvigelser simuleres for at kvantificere påvirkningen på løftet. På basis af disse resultater udvikles en reduceret ordens model, som kan forudsige den nødvendige flapvinkel til at modvirke vindstød; modellen implementeres som brugerdefinerede funktioner, der også håndterer den deformérbare beregningsmesh, ændret geometri og tidsvarierende indløbshastighed. Systemet afprøves i repræsentative vindstødsscenarier, hvor de fleste tilfælde aflastes effektivt, særligt når hastighedsgradienterne er små. Arbejdet er afgrænset til to-dimensionel, stiv vinge-aerodynamik og behandler ikke strukturel respons eller flappens mekaniske design.
This thesis investigates how to reduce gust-induced loads on a two-dimensional airfoil using a CFD-based control system that drives a trailing edge flap. A computational fluid dynamics model in Ansys Fluent, employing the Spalart–Allmaras turbulence model and focused on accurate lift prediction, is developed and validated against experimental surface pressure and boundary-layer velocity profiles (Nakayama, 1985), showing good agreement. The effects of both horizontal and vertical gusts and various flap deflections on lift are simulated. Based on these results, a reduced-order model is constructed to predict the flap angle needed to counter incoming gusts; it is implemented as user-defined functions that also manage a deforming mesh, airfoil geometry changes, and time-varying inlet velocities. The gust load alleviation system is tested in representative gust cases, and most are mitigated effectively, with better performance for gusts with smaller velocity gradients. The study is limited to two-dimensional, rigid-wing aerodynamics and does not address structural dynamics or flap actuator design.
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