The effects of structural and aerodynamic nonlinearities on the energy harvesting from airfoil stall-induced oscillations

Autor(es)

dos Santos, Carlos R. ^[1] ; Marques, Flavio D. ^[1] ; Hajj, Muhammad R. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Mech Engn, Sao Carlos, SP - Brazil

^[2] Davidson Lab, Dept Civil Environm & Ocean Engn, Hoboken, NJ - USA

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF VIBRATION AND CONTROL; v. 25, n. 14, p. 1991-2007, JUL 2019.
• Citações Web of Science: 0

Resumo

An airfoil may undergo stall-induced oscillations beyond the critical flutter speed with amplitudes determined by aerodynamic nonlinearities due to the dynamic stall. Stall-induced oscillations yield intense periodical motions that can be used to convert the airflow energy into electrical power. The inclusion of structural nonlinearities contributes to the complexity of the aeroelastic response. In this sense, the present work models and analyzes for the first time the effects of structural and aerodynamic nonlinearities in the potential of extracting energy from pitching and plunging motions of an airfoil during stall-induced oscillations. A computational model is employed, based on the electro-aeroelastic differential equations modeling a typical aeroelastic section with two degrees of freedom with an electrical generator connected to the pitching motion and a piezoelectric element connected to the plunging motion. The Beddoes-Leishman semi-empirical model is used to represent the unsteady aerodynamic loading. Concentrated structural nonlinearities, such as the hardening effect and free-play, are also considered. Bifurcation diagrams and harvested power calculations are used to analyze the performance of each energy harvesting scheme. The results show that nonlinear pitching stiffness reduces the average harvested power from this degree of freedom in a range of wind speeds. However, the presence of a free-play spring reduces the flutter velocity and initiates the harvesting at lower wind speeds. In conclusion, the present electro-aeroelastic model can be used to find optimal parameters of a harvester from airfoil stall-induced oscillations for a specific application. (AU)

• Processo FAPESP: 17/02926-9 - Levantamento do carregamento aerodinâmico não estacionário de aerofólio na condição de estol dinâmico para ajuste de modelos semi-empíricos
• Beneficiário: Flávio Donizeti Marques
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/09468-6 - Otimização do processo de extração de energia de oscilações induzidas pelo estol em aerofólios
• Beneficiário: Carlos Renan dos Santos
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto