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Large Eddy Simulations of Aircraft Icing Aerodynamics.
Large Eddy Simulations of Aircraft Icing Aerodynamics.
상세정보
- 자료유형
- 학위논문
- Control Number
- 0017163762
- International Standard Book Number
- 9798342111690
- Dewey Decimal Classification Number
- 600
- Main Entry-Personal Name
- Bornhoft, Brett.
- Publication, Distribution, etc. (Imprint
- [S.l.] : Stanford University., 2024
- Publication, Distribution, etc. (Imprint
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- Physical Description
- 163 p.
- General Note
- Source: Dissertations Abstracts International, Volume: 86-04, Section: B.
- General Note
- Advisor: Moin, Parviz.
- Dissertation Note
- Thesis (Ph.D.)--Stanford University, 2024.
- Summary, Etc.
- 요약Predicting the aerodynamic performance of aircraft in icing conditions is crucial for ensuring flight safety. Modeling icing and its effect on aerodynamics has recently garnered attention in academia and industry due to the changes to the Code of Federal Regulations (CFR) in 2007 and 2014. The changes state that the certification of transport-category airplanes requires the same handling/performance in both icing and non-icing conditions. This has motivated airplane designers to include icing effects in the first stage of the design process. The accurate prediction of the effects of ice shapes on the aerodynamic performance of airfoils and wings is considered an industry gap that we address in this dissertation (Mauery et al., 2021).Encouraged by recent studies using large eddy simulations (LES) that demonstrate the ability to predict stall characteristics on full aircraft with smooth wings at an affordable cost (Goc et al., 2021), this dissertation applies this methodology to icing conditions. Using laser-scanned, detailed representations of the icing geometries, wall-modeled LES (WMLES) calculations are conducted to compare integrated loads against experimental measurements in a variety of icing conditions, including early-time glaze, early-time rime, streamwise, horn, and spanwise ridge ice formations. These ice geometries, mounted to a NACA23012 airfoil, span the space of ice shape types as described in (Bragg et al., 2005). Good agreement is achieved for the early-time glaze, streamwise, horn, and spanwise ridge ice geometries. At low angles of attack, reduced span representations were adequate to capture the aerodynamic quantities of interest (lift, drag, moments, and pressure distributions), but at high angles of attack (at and beyond the stall angle), it was shown that using larger spanwise extents is necessary for achieving an accurate representation of the aerodynamic performance coefficients. In contrast to the other geometries, the rime ice geometry simulations showed inaccurate predictions of the quantities of interest. This is attributed to the resolution of the roughness elements, which was completely sub-grid at the resolutions tested. To address this issue, a new roughness wall model is developed.For a turbulent rough-wall flow, it is known that the outer layer of a turbulent boundary layer is independent of wall roughness effects except in the roughness's role in setting both the friction velocity and boundary layer thickness (Jimenez, 2004; Kadivar et al., 2021). Therefore, to appropriately model these effects, a database of direct numerical simulations (DNS) of rough-wall turbulent channel flows is constructed and used to parameterize the rough-wall turbulent boundary layer using three roughness parameters: the root-mean-square roughness height, the surface effective slope, and its skewness. From this parameterization, we develop and introduce a velocity transformation for rough-wall turbulent flows and apply it as a modification to the equilibrium wall model (EQWM). This new wall model is then tested in both a turbulent channel flow and the early-time rime ice geometry. In both cases, we observe large improvements in both local quantities, such as velocity profiles, but also in integrated quantities, such as lift and drag, when augmenting the EQWM with the newly obtained roughness velocity transformation.
- Subject Added Entry-Topical Term
- Friction.
- Subject Added Entry-Topical Term
- Aircraft.
- Subject Added Entry-Topical Term
- Aeronautics.
- Subject Added Entry-Topical Term
- Viscosity.
- Subject Added Entry-Topical Term
- Reynolds number.
- Subject Added Entry-Topical Term
- Geometry.
- Subject Added Entry-Topical Term
- Mechanical engineering.
- Subject Added Entry-Topical Term
- Shear stress.
- Subject Added Entry-Topical Term
- Aerospace engineering.
- Subject Added Entry-Topical Term
- Fluid mechanics.
- Added Entry-Corporate Name
- Stanford University.
- Host Item Entry
- Dissertations Abstracts International. 86-04B.
- Electronic Location and Access
- 로그인을 한후 보실 수 있는 자료입니다.
- Control Number
- joongbu:655055
MARC
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■006m o d
■007cr#unu||||||||
■020 ▼a9798342111690
■035 ▼a(MiAaPQ)AAI31520345
■035 ▼a(MiAaPQ)Stanfordyh160kg7422
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a600
■1001 ▼aBornhoft, Brett.
■24510▼aLarge Eddy Simulations of Aircraft Icing Aerodynamics.
■260 ▼a[S.l.]▼bStanford University. ▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a163 p.
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-04, Section: B.
■500 ▼aAdvisor: Moin, Parviz.
■5021 ▼aThesis (Ph.D.)--Stanford University, 2024.
■520 ▼aPredicting the aerodynamic performance of aircraft in icing conditions is crucial for ensuring flight safety. Modeling icing and its effect on aerodynamics has recently garnered attention in academia and industry due to the changes to the Code of Federal Regulations (CFR) in 2007 and 2014. The changes state that the certification of transport-category airplanes requires the same handling/performance in both icing and non-icing conditions. This has motivated airplane designers to include icing effects in the first stage of the design process. The accurate prediction of the effects of ice shapes on the aerodynamic performance of airfoils and wings is considered an industry gap that we address in this dissertation (Mauery et al., 2021).Encouraged by recent studies using large eddy simulations (LES) that demonstrate the ability to predict stall characteristics on full aircraft with smooth wings at an affordable cost (Goc et al., 2021), this dissertation applies this methodology to icing conditions. Using laser-scanned, detailed representations of the icing geometries, wall-modeled LES (WMLES) calculations are conducted to compare integrated loads against experimental measurements in a variety of icing conditions, including early-time glaze, early-time rime, streamwise, horn, and spanwise ridge ice formations. These ice geometries, mounted to a NACA23012 airfoil, span the space of ice shape types as described in (Bragg et al., 2005). Good agreement is achieved for the early-time glaze, streamwise, horn, and spanwise ridge ice geometries. At low angles of attack, reduced span representations were adequate to capture the aerodynamic quantities of interest (lift, drag, moments, and pressure distributions), but at high angles of attack (at and beyond the stall angle), it was shown that using larger spanwise extents is necessary for achieving an accurate representation of the aerodynamic performance coefficients. In contrast to the other geometries, the rime ice geometry simulations showed inaccurate predictions of the quantities of interest. This is attributed to the resolution of the roughness elements, which was completely sub-grid at the resolutions tested. To address this issue, a new roughness wall model is developed.For a turbulent rough-wall flow, it is known that the outer layer of a turbulent boundary layer is independent of wall roughness effects except in the roughness's role in setting both the friction velocity and boundary layer thickness (Jimenez, 2004; Kadivar et al., 2021). Therefore, to appropriately model these effects, a database of direct numerical simulations (DNS) of rough-wall turbulent channel flows is constructed and used to parameterize the rough-wall turbulent boundary layer using three roughness parameters: the root-mean-square roughness height, the surface effective slope, and its skewness. From this parameterization, we develop and introduce a velocity transformation for rough-wall turbulent flows and apply it as a modification to the equilibrium wall model (EQWM). This new wall model is then tested in both a turbulent channel flow and the early-time rime ice geometry. In both cases, we observe large improvements in both local quantities, such as velocity profiles, but also in integrated quantities, such as lift and drag, when augmenting the EQWM with the newly obtained roughness velocity transformation.
■590 ▼aSchool code: 0212.
■650 4▼aFriction.
■650 4▼aAircraft.
■650 4▼aAeronautics.
■650 4▼aViscosity.
■650 4▼aReynolds number.
■650 4▼aGeometry.
■650 4▼aMechanical engineering.
■650 4▼aShear stress.
■650 4▼aAerospace engineering.
■650 4▼aFluid mechanics.
■690 ▼a0548
■690 ▼a0538
■690 ▼a0204
■71020▼aStanford University.
■7730 ▼tDissertations Abstracts International▼g86-04B.
■790 ▼a0212
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17163762▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
