Aerodynamic investigation of the deformable membrane airfoil with excess length

Abstract

Original scientific paper The deformable membrane airfoils (DMA) are considered in the present paper, which could be potentially used on a new class of modern Micro Aerial Vehicles for their compact and lightweight form. Numerical simulations of low Reynolds number airflow around the DMA with excess length were performed and compared with the results obtained in the experiment. The aerodynamic performance was studied using a fluid-structure interaction between the DMA with excess length and the surrounding fluid flow. Fluid part was solved using Reynolds averaged Navier -Stokes (RANS) equations and applying the resulting pressure distribution to the airfoil. Experiment was performed in the low-turbulence wind tunnel with a model of an airfoil made from a deformable membrane with excess length, fixed at the leading and trailing edge. Measurements were obtained for the predetermined range of excess length ratio (0,025 to 0,150) and angle of incidence (0° to 15°), and showed a reasonable agreement with the numerical results with smallest discrepancies at 1,8 %. Investigation of the excess length shows that it could increase longitudinal stability of the airfoil in the non-oscillating regime, compared to standard rigid airfoils. Keywords: deformable membrane airfoil; experimental validation; fluid-structure interaction; RANS simulation Aerodinamičko istraživanje deformabilnog membranskog aeroprofila s pretičkom duljineIzvorni znanstveni članak U članku su predstavljeni deformabilni membranski aeroprofili (DMA), koji bi se zbog kompaktnosti i lakoće potencijalno mogli koristiti kod nove klase suvremnih mikro bespilotnih letjelica. Izvedena je numerička studija strujanja fluida s niskim Reynoldsovim brojem oko DMA s pretičkom duljine i uspoređena s rezultatima dobivenim u eksperimentu. Za istraživanje aerodinamičkih performansi, provedene su simulacije interakcije između fluida i DMA, s rješavanjem Reynolds osrednjenih Navier-Stokesovih jednadžbi (RANS) i primjenjujući raspodjele hidrodinamičkog tlaka na aeroprofil. Eksperiment je proveden u zračnom tunelu male turbulencije na modelu aeroprofila izrađenom od deformabilne membrane s pretičkom duljine, koja je na prednjem i stražnjem rubu omotana oko čelične šipke. Mjerjenja su provedena za unaprijed određeni raspon kvocijenta pretička duljine (od 0,025 do 0,150) i napadnog kuta (0° to 15°) i ustanovljena su dobra slaganja s rezultatima numeričke simulacije s najmanjim prosečnim odstupanjem kvocijenta uzgona 1,8 %. Istraživanje utjecaja pretička duljine membrane pokazuje, da bi to moglo poboljšati longitudinalnu stabilnost aeroprofila u radnom režimu bez oscilacija, u odnosu na krute aeroprofile.Ključne riječi: deformabilni membranski aeroprofil; eksperimentalna validacija; interakcija fluida i structure; RANS simulacije