Aerodynamic analysis of an oscillating airfoil in a power-extraction regime using the compressible Navier-Stokes equations with efficient and accurate low-speed preconditioning

diploma work

Jernej Drofelnik (Author), Leopold Škerget (Mentor), M. Sergio Campobasso (Co-mentor)

Abstract

A wing that is simultaneously heaving and pitching may extract energy from an oncoming air flow, thus acting as turbine. The purpose of this study was to analyse the relationship between the aerodynamics and the theoretical performance of this device by means of timedependent laminar flow simulations performed with a research compressible finite volume Navier-Stokes solver COSA. In presented analyses, which confirm the findings of another independent study, the efficiency of the power extraction of this device can be of the order of 35 %, and such an efficient operating condition is characterized due to the favourable effects of a strong dynamic stall. This study is a part of a wider research programme of Dr. Campobasso’s group at University of Glasgow, aiming to develop a general-purpose computational framework for unsteady aerodynamic and aeroacoustic wind energy engineering. In view of aeroacoustic applications, the developed flow solver uses the compressible formulation of the Navier-Stokes equations with carefully optimized low-speed preconditioning. To demonstrate the modeling capabilities, the accuracy and the high computational performance of the developed low-speed preconditioning technology, the unsteady aerodynamics of the energy-extracting device is simulated by using a computationally challenging freestream Mach number of 0.001. A mixed preconditioning strategy that maintains both the nominal accuracy and the computational efficiency of the solver also for time-dependent low-speed problems is presented. A fundamental element of novelty of this study is a thorough assessment of the proposed approach partly based on the challenging and realistic problem associated with the oscillating wing device.

Keywords

computational fluid dynamics;compressible fluid flow;oscilating wing device;laminar flow simulations;simulations;COSA;wind energy engineering;aeroacoustics;finite volume method;Navier-Stokes equations;

Data

Language:	English
Year of publishing:	2012
Source:	Maribor
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FS - Faculty of Mechanical Engineering
Publisher:	[J. Drofelnik]
UDC:	533.6.011.8(043.2)
COBISS:	16974614
Views:	2107
Downloads:	134
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Other data

Secondary language:	Slovenian
Secondary title:	Aerodinamična analiza nihajočega krila v energijsko-ekstrakcijskem režimu z uporabo stisljivih Navier-Stokesovih enačb z učinkovitim in natančnim nizko-hitrostnim predpogojevalnikom
Secondary abstract:	V zračnem toku nihajoče krilo, ki se sočasno nagiba okrog prečne osi, lahko deluje kot turbina. Namen študije je analiza odvisnosti aerodinamike in teoretične zmogljivosti te naprave s pomočjo časovno-odvisnih laminarnih tokovnih simulacij, izvedenih z akademskim programskim paketom COSA, ki uporablja formulacijo Navier-Stokesovih enačb nestacionarnega gibanja newtonske viskozne stisljive tekočine na osnovi metode končnih volumnov. Analiza potrjuje ugotovitve druge neodvisne študije, da lahko ta naprava dosega izkoristke v območju 35 %. Dober izkoristek je posledica ugodnih učinkov močnega odtrganja zračnega toka iz krila. Študija je del širšega raziskovalnega programa, ki ga vodi Dr. Campobasso na Univerzi v Glasgowu, ki razvija splošen programski sestav za reševanje problemov nestacionarne aerodinamike in aeroakustike vetrno-energijskega inženiringa. Glede na aeroakustične aplikacije uporablja COSA Navier-Stokesove enačbe za stisljivo tekočino s skrbno oblikovanim nizko-hitrostnim predpogojevalnikom. Za demonstracijo zmožnosti, natančnosti in visoke računske zmogljivosti razvite nizko-hitrostne predpogojevalne tehnologije, je bila simulirana nestacionarna aerodinamika energijsko-ekstrakcijske naprave, z uporabo zahtevnega prosto-tokovnega Machovega števila 0.001. Predstavljena je strategija mešanega nizkohitrostnega predpogojevalnika, ki vzdržuje nominalno natančnost in računsko učinkovitost programskega paketa tudi za časovno-odvisne nizko-hitrostne probleme. Bistvena novost je temeljita ocena predlaganega pristopa, delno zasnovanega na zahtevnem in realističnem problemu, povezanem z napravo z nihajočim krilom.
Secondary keywords:	dinamika tekočin;računalniška dinamika tekočin;stisljivost tekočin;aerodinamika;simulacija laminarnega toka;programski paket COSA;metoda končnih volumnov;večmrežna metoda;aerodinamična analiza nihajočega krila;diplomske naloge;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za strojništvo
Pages:	XX, 59 str.
Keywords (UDC):	mathematics;natural sciences;naravoslovne vede;matematika;physics;fizika;mechanics of gases;aeromechanics;plasma physics;mehanika plinov;aeromehanika;fizika plazme;aerodynamics;
ID:	81416