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High order matched interface and boundary method for elliptic equations with discontinuous coefficients and singular sources
, 2006
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Numerical Methods for FluidStructure Interaction  A Review
, 2012
"... The interactions between incompressible fluid flows and immersed structures are nonlinear multiphysics phenomena that have applications to a wide range of scientific and engineering disciplines. In this article, we review representative numerical methods based on conforming and nonconforming me ..."
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The interactions between incompressible fluid flows and immersed structures are nonlinear multiphysics phenomena that have applications to a wide range of scientific and engineering disciplines. In this article, we review representative numerical methods based on conforming and nonconforming meshes that are currently available for computing fluidstructure interaction problems, with an emphasis on some of the recent developments in the field. A goal is to categorize the selected methods and assess their accuracy and efficiency. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study in fluidstructure interactions.
Matched interface and boundary (MIB) method for elliptic problems with sharpedged interfaces
, 2007
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TETHER FORCE CONSTRAINTS IN STOKES FLOW BY THE IMMERSED BOUNDARY METHOD ON A PERIODIC DOMAIN
, 2009
"... The immersed boundary method is an algorithm for simulating the interaction of immersed elastic bodies or boundaries with a viscous incompressible fluid. The immersed elastic material is represented in the fluid equations by a system or field of applied forces. The particular case of Stokes flow wi ..."
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The immersed boundary method is an algorithm for simulating the interaction of immersed elastic bodies or boundaries with a viscous incompressible fluid. The immersed elastic material is represented in the fluid equations by a system or field of applied forces. The particular case of Stokes flow with applied forces on a periodic domain involves two related mathematical complications. One of these is that an arbitrary constant vector may be added to the fluid velocity, and the other is the constraint that the integral of the applied force must be zero. Typically, forces defined on a freely floating elastic immersed boundary or body satisfy this constraint, but there are many important classes of forces that do not. For example, the socalled tether forces that are used to prescribe the simulated configuration of an immersed boundary, possibly in a timedependent manner, typically do not sum to zero. Another type of force that does not have zero integral is a uniform force density that may be used to simulate an overall pressure gradient driving flow through a system. We present a method for periodic Stokes flow that when used with tether points, admits the use of all forces irrespective of their integral over the domain. A byproduct of this method is that the additive constant velocity associated with periodic Stokes flow is uniquely determined. Indeed, the additive constant is chosen at each time step so that the sum of the tether forces balances the sum of any other forces that may be applied.
2007: Technical summary
 In Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change
"... A postcompletion error occurs when the final step of a task is omitted because the main goal of the task is thought to be completed (Byrne & Bovair, 1997). Postcompletion errors are more likely to occur after interruptions (Ratwani, McCurry & Trafton, 2008). Global placekeeping cues (Gray, 2 ..."
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A postcompletion error occurs when the final step of a task is omitted because the main goal of the task is thought to be completed (Byrne & Bovair, 1997). Postcompletion errors are more likely to occur after interruptions (Ratwani, McCurry & Trafton, 2008). Global placekeeping cues (Gray, 2000) allow a user to track their progress in a task and may be a method for reducing the rate of postcompletion errors. A computerbased procedural task with a postcompletion step was used in this experiment to determine how the interaction of global placekeeping cues with interruptions would affect postcompletion errors. These results suggest that global placekeeping cues reduce the postcompletion error rate after interruptions, but that global placekeeping does not completely eliminate postcompletion errors.
11.1 DEVELOPMENT OF AN IMMERSED BOUNDARY METHOD TO RESOLVE COMPLEX TERRAIN IN THE WEATHER RESEARCH AND FORECASTING MODEL
"... Flow and dispersion processes in urban areas are profoundly influenced by the presence of buildings which divert mean flow, affect surface heating and cooling, and alter the structure of turbulence in ..."
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Flow and dispersion processes in urban areas are profoundly influenced by the presence of buildings which divert mean flow, affect surface heating and cooling, and alter the structure of turbulence in
LargeScale Source Term Modeling of Vortex Generation
"... Methods of modeling vortex generation in computational fluid dynamics without meshing the vortex generating device have been investigated. This is done by adding source terms to the governing equations to create vortices. Previous work in this area has focused on boundary layer control. This study ..."
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Methods of modeling vortex generation in computational fluid dynamics without meshing the vortex generating device have been investigated. This is done by adding source terms to the governing equations to create vortices. Previous work in this area has focused on boundary layer control. This study looks at larger scale applications, such as using vortices for force enhancement. Two different approaches are tested. One is to model vortex generators directly, for which an existing method that replaces the force exerted on the fluid by a vortex generator with a source term is used. Also of this type, a simple immersed boundary method is used for comparison. The other approach uses source terms to create specified vortex velocity profiles. A method to add a continuous threedimensional velocity is formulated and implemented in three ways; explicit calculation of the required forces from the NavierStokes equations, direct forcing (setting the velocity as boundary conditions), and penaltytype feedback forcing. After basic testing, all methods are applied in a practical engineering case using a commercial solver. Nomenclature A Function specifying the axial variation of additional axial velocity uχa b ̂ Unit vector in the direction of the span of a vortex generator C Various constants distinguished by subscript Cp Pressure coefficient c Chord, m d Axial length of source term region, m f Body force, N/m3 h Vortex generator height, m I Represents an integral l ̂ Unit vector in the direction of a force n ̂ Unit vector normal to vortex generator planform p Pressure, N/m2 Q Second invariant of ∇u, Q ≡ 1
TOWARD A GPUACCELERATED IMMERSED BOUNDARY METHOD FOR WIND FORECASTING OVER COMPLEX TERRAIN
"... A shorfterm wind power fo recasting capability can be a valuable 100 / in the renewable energy indus/IJI to addre.'iS loadbalancing issues that a";se from intermillent wind field", A lthough numerical.... veather prediction models have been used to forecast winds, their applicabilit ..."
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A shorfterm wind power fo recasting capability can be a valuable 100 / in the renewable energy indus/IJI to addre.'iS loadbalancing issues that a";se from intermillent wind field", A lthough numerical.... veather prediction models have been used to forecast winds, their applicability to microscale atmo::.pheric boundary layer flows and ahililY to predict wind speeds at turbine hub height with a desired accuracy is not clear. To address this issue, we develop a mulliCPU parallel flow solver to forecaslwinds over complex terrain at (he micfVscale, where computational domain size can range from meters to several kilometers. In the solver. \VC adopt the immersed boundQly method and the Lagrangian dynamic largeeddy simulation model and extend them 10 aJmospheric jlows. The compulations are accelerated on CPU clusters with a duallevel parallel implementation that interleaves lvIPI with CUDA. We evaluate the flow solver components against test proh/ems and obtain preliminwy results offlow over Bolund Hill, a coastal hill in Denmark.
Accurate ImmersedBoundary Reconstructions for Viscous Flow Simulations
"... Immersedboundary reconstruction schemes for enforcing boundary conditions on surfaces not aligned with grid lines are presented. The flow dynamics in the nearwall regions is fundamental to correctly predict the overall flow, especially in the presence of turbulence. In the current approach, geomet ..."
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Immersedboundary reconstruction schemes for enforcing boundary conditions on surfaces not aligned with grid lines are presented. The flow dynamics in the nearwall regions is fundamental to correctly predict the overall flow, especially in the presence of turbulence. In the current approach, geometrical information and physical conservation constraints are used to build accurate solution reconstructions; in addition, the issue of consistent discretization in the cells crossed by the immersed boundary is treated. A novel interpolation method based on momentum balance and mass conservation based onfinite volumemethodare introduced to correctly predict the velocity andpressurefield in the vicinity of the boundaries. The assessment of the solution quality is based on calculations of Taylor decaying vortices. Examples of laminar and turbulent flow calculations are also reported. Nomenclature a = amplitude of a wave ai;j, bi;j = coefficient of velocity interpolation formula Cp = pressure coefficient d = diameter f = frequency L = reference length