Dissertations / Theses on the topic 'Spectral flow'
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Meng, Sha. "A spectral element method for viscoelastic fluid flow." Thesis, De Montfort University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369907.
Full textAven, Matthew. "Daily Traffic Flow Pattern Recognition by Spectral Clustering." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/cmc_theses/1597.
Full textButsuntorn, Nawee. "Time spectral method for rotorcraft flow with vorticity confinement /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Full textAzamov, Nurulla, and azam0001@infoeng flinders edu au. "Spectral shift function in von Neumann algebras." Flinders University. Informatics and Engineering, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20080129.121422.
Full textParkinson, Steven. "Modelling free-surface flow with bathymetry variation using spectral methods." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570859.
Full textLott, P. Aaron. "Fast solvers for models of fluid flow with spectral elements." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8743.
Full textThesis research directed by: Applied Mathematics & Statistics, and Scientific Computation Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
David, Jean-Yves. "Modern spectral analysis techniques for blood flow velocity and spectral measurements with a 20 MHZ pulsed doppler ultrasound catheter." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/17791.
Full textTugluk, Ozan. "Direct Numerical Simulation Of Pipe Flow Using A Solenoidal Spectral Method." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614293/index.pdf.
Full textAkcan, Zekai. "Uniform flow past a rigid sphere by the spectral numerical methods." Thesis, Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/9101.
Full textA steady, axially symmetric, incompressible, viscous flow past a rigid sphere is numerically simulated by using a numerical scheme, based on spectral methods. The equations have been reduced to two sets of nonlinear second order partial differential equations in terms of vorticity and stream function. The calculations have been carried out for Reynolds numbers, based on the sphere diameter, in the range 0.1 to 104. The numerical results have verified that there is excellent agreement with Stokes theory at very low Reynolds numbers. At moderate to intermediate Reynolds numbers there is good general agreement with available experimental data and flow visualization pictures. The Reynolds number at which separation occurs is estimated as 20. The approach to boundary-layer behavior with increasing Reynolds numbers is also verified by comparison with potential flow theory and analytical boundary-layer solution.
Chaurasia, Hemant Kumar. "A time-spectral hybridizable discontinuous Galerkin method for periodic flow problems." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90647.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 110-120).
Numerical simulations of time-periodic flows are an essential design tool for a wide range of engineered systems, including jet engines, wind turbines and flapping wings. Conventional solvers for time-periodic flows are limited in accuracy and efficiency by the low-order Finite Volume and time-marching methods they typically employ. These methods introduce significant numerical dissipation in the simulated flow, and can require hundreds of timesteps to describe a periodic flow with only a few harmonic modes. However, recent developments in high-order methods and Fourier-based time discretizations present an opportunity to greatly improve computational performance. This thesis presents a novel Time-Spectral Hybridizable Discontinuous Galerkin (HDG) method for periodic flow problems, together with applications to flow through cascades and rotor/stator assemblies in aeronautical turbomachinery. The present work combines a Fourier-based Time-Spectral discretization in time with an HDG discretization in space, realizing the dual benefits of spectral accuracy in time and high-order accuracy in space. Low numerical dissipation and favorable stability properties are inherited from the high-order HDG method, together with a reduced number of globally coupled degrees of freedom compared to other DG methods. HDG provides a natural framework for treating boundary conditions, which is exploited in the development of a new high-order sliding mesh interface coupling technique for multiple-row turbomachinery problems. A regularization of the Spalart-Allmaras turbulence model is also employed to ensure numerical stability of unsteady flow solutions obtained with high-order methods. Turning to the temporal discretization, the Time-Spectral method enables direct solution of a periodic flow state, bypasses initial transient behavior, and can often deliver substantial savings in computational cost compared to implicit time-marching. An important driver of computational efficiency is the ability to select and resolve only the most important frequencies of a periodic problem, such as the blade-passing frequencies in turbomachinery flows. To this end, the present work introduces an adaptive frequency selection technique, using the Time-Spectral residual to form an inexpensive error indicator. Having selected a set of frequencies, the accuracy of the Time-Spectral solution is greatly improved by using optimally selected collocation points in time. For multi-domain problems such as turbomachinery flows, an anti-aliasing filter is also needed to avoid errors in the transfer of the solution across the sliding interface. All of these aspects contribute to the Adaptive Time-Spectral HDG method developed in this thesis. Performance characteristics of the method are demonstrated through applications to periodic ordinary differential equations, a convection problem, laminar flow over a pitching airfoil, and turbulent flow through a range of single- and multiple-row turbomachinery configurations. For a 2:1 rotor/stator flow problem, the Adaptive Time-Spectral HDG method correctly identifies the relevant frequencies in each blade row. This leads to an accurate periodic flow solution with greatly reduced computational cost, when compared to sequentially selected frequencies or a time-marching solution. For comparable accuracy in prediction of rotor loading, the Adaptive Time- Spectral HDG method incurs 3 times lower computational cost (CPU time) than time-marching, and for prediction of only the 1st harmonic amplitude, these savings rise to a factor of 200. Finally, in three-row compressor flow simulations, a high-order HDG method is shown to achieve significantly greater accuracy than a lower-order method with the same computational cost. For example, considering error in the amplitude of the 1st harmonic mode of total rotor loading, a p = 1 computation results in 20% error, in contrast to only 1% error in a p = 4 solution with comparable cost. This highlights the benefits that can be obtained from higher-order methods in the context of turbomachinery flow problems.
by Hemant Kumar Chaurasia.
Ph. D.
Walther, Julia, and Edmund Koch. "Lateral resonant Doppler flow measurement by spectral domain optical coherence tomography." SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A34981.
Full textAbolmoali, Philip. "Spectral Energy Transfers in Transonic Cavity Flows with High Frequency Flow Control from Powered Resonance Tubes." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511867795447293.
Full textMelotte, David John. "Superfluid turbulence." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287825.
Full textElling, Volker Wilhelm. "A spectral method for mapping dataflow graphs." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8161.
Full textZeybek, Birol. "Numerical simulation of flow induced by a spinning sphere using spectral methods." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA331206.
Full textCagnone, Jean-Sébastien. "A non linear frequency domain-spectral difference scheme for unsteady periodic flows /." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111614.
Full textDumas, Guy Leonard Anthony. "Study of spherical couette flow via 3-D spectral simulations : large and narrow-gap flows and their transitions /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-04162004-103555.
Full textDechamps, Xavier. "Numerical simulation of incompressible magnetohydrodynamic duct and channel flows by a hybrid spectral, finite element solver." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209203.
Full textDoctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Engin, Erjona. "Dynamic Analysis Of Flow In Two Dimensional Flow." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609374/index.pdf.
Full textve (KL) decomposition is widely used in computational fluid dynamics to achieve reduced storage requirements or construction of relatively low-dimensional models. In this study the KL basis is extracted from the flow field obtained from the direct numerical simulation of the Poiseuille flow.
Akdag, Osman. "Incompressible Flow Simulations Using Least Squares Spectral Element Method On Adaptively Refined Triangular Grids." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614944/index.pdf.
Full textLaird, Alistair. "A hybrid spectral discretisation and iterative solution methods for acoustic models in potential flow." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403764.
Full textShin, James Jang-Sik. "A spectral element formulation for fluid-structure interactions : applications to flow through collapsible channels." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41003.
Full textBellis, Stephen John. "VLSI implementation of a spectral estimator for use with pulsed ultrasonic blood flow detectors." Thesis, Bangor University, 1996. https://research.bangor.ac.uk/portal/en/theses/vlsi-implementation-of-a-spectral-estimator-for-use-with-pulsed-ultrasonic-blood-flow-detectors(aada8831-f06d-4e23-94d6-341d021a3e62).html.
Full textBrooks, Donald Ray. "Development of Specialized Laser Doppler Velocimeters for High Resolution Flow Profile and Turbulence Spectral Measurements." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/78089.
Full textMaster of Science
Cerocchi, Filippo. "Dynamical and Spectral applications of Gromov-Hausdorff Theory." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM077/document.
Full textThis Ph.D. Thesis is divided into two parts. In the first part we present the barycenter method, a technique which has been introduced by G. Besson, G. Courtois and S. Gallot in 1995, in order to solve the Minimal Entropy conjecture. In Chapter 1 we are interested in the more recent developments of this method, more precisely in the recent extension of the method to the case of manifolds having sectional curvature of variable sign. In Chapters 2 and 3 we shall present some new results whose proofs make use of the barycenter method. The Conjugacy Rigidity problem is the theme of Chapter 2. First we show a general result which provide a comparison between the large scale geometry of the Riemannian universal coverings of two compact manifolds whose geodesic flows are conjugates. Then we shall show how we can apply the latter result and the barycenter method in curvature of variable sign in order to give a new proof of the conjugacy rigidity of flat manifolds. In Chapter 3 we shall give a proof of a spectra comparison theorem for a compact Riemannian manifold which admits a Gromov-Hausdorff-approximation of non zero absolute degree on a fixed compact manifold (X,g') and which has volume almost smaller than the one of the reference manifold. The proof relies on the barycenter method in curvature of variable sign and on iterated Sobolev inequalities. We underline that it is an approximation result (and not just a convergence result) and that no curvature assumptions are made or inferred on (Y,g). The second part of the Thesis consists of a single chapter. In this chapter we prove a Margulis Lemma without curvature assumptions for Riemannian manifolds having decomposable 2-torsionless fundamental group. We shall give also a proof of a universal lower bound for the homotopy systole of compact Riemannian manifolds having bounded volume entropy and diameter, and decomposable torsionless fundamental group. As a consequence of the latter result we shall deduce a Precompactness and Finiteness theorem and a Volume estimate without curvature assumptions
Alescio, Giuseppe. "Chebyshev spectral method for incompressible viscous flow with boundary layer control via suction or blowing." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35585.
Full textIncludes bibliographical references (p. 155-157).
The MISES quasi 3-D design/analysis code implements a two-equation integral method with empirical closure relations to solve the boundary layer flow problem with or without suction, but lacks the option of flow control via blowing. The integral method is parameterized with the shape parameter H _ 6*/0 which cannot be applied to the blowing problem since 0 - 0 downstream of the injection slot causing H -, co - a computational disaster. In this thesis, two alternate approaches are proposed to solve the blowing problem. First, a two-equation integral method parameterized with the profile parameters of a multi-deck representation of a turbulent jet based on Coles' law of the wake was formulated. The appearance of spurious singularities in the Jacobian matrices associated with the system of equations and the vector of unknowns prevented this method from being implemented. Second, a Chebyshev spectral method using the wall function technique was applied to the defect form of the incompressible viscous momentum equation. A turbulent jet profile was computed with N = 40 modes, a number low enough to allow the method's implementation into the MISES framework.
(cont.) For the spectral approach, a stand-alone code was developed to solve laminar and turbulent flow over a flat plate with the following configurations: solid wall, porous wall with vertical suction/blowing, and fluid injection from an inclined slot. For the turbulent case, the Reynolds stress was replaced with a composite model for the eddy viscosity based on Spalding's law of the wall for the inner layer and Clauser's outer layer formulation. In the laminar regime, N - 10 modes are required for an accurate solution whereas the two-layer structure of a turbulent boundary layer increases this number to N 100 modes. The incorporation of a wall function, consistent with the inner layer eddy viscosity model, in the approximation of the streamwise velocity, reduced the required number of modes by an order of magnitude - a major computational advantage. The more general Spalart-Allmaras turbulence model was implemented in the spectral formulation to investigate the effect of using a wall function based on Spalding's law of the wall.
(cont.) For the flat plate case (solid wall), a small inconsistency between the wall function and the eddy viscosity model produced an erroneous shear stress near the wall. Nevertheless, the velocity profile was in close agreement with an accurate representation constructed from Spalding's law of the wall and Coles' law of the wake.
by Giuseppe Alescio.
Ph.D.
Silas, Kevin Alexander. "Phase Transform Time Delay Estimation to Counteract Spectral Haystacking Effects in Jet Exhaust Flow Measurements." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104892.
Full textMaster of Science
This study builds on a Computational Tomography (CT) technique that uses an acoustic signal and an array of receivers to measure the velocity and temperature of a gas flow field. In particular, the velocity and temperature field tested involves multiple turbulent and disruptive elements, requiring a loud and specifically designed signal. As such, a novel acoustic signal generator, the dual Hartmann generator, was designed that is both loud and produces a specific two-toned signal. The key contribution of the study was to process the data, comparing the sets of transmitted and received signals, in order to estimate the time delay amongst receiver pairs – a key input in the CT method. Traditional cross-correlation methods were inadequate, and multiple alternatives were evaluated. The Phase Transform (PHAT) technique showed the most promise, and an explanation is given for why this technique is most suitable for this type of signal.
Yu, Bo. "Surface Mean Flow and Turbulence Structure in Tropical Cyclone Winds." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/25.
Full textMerle, Matthieu. "Approches numériques pour l'analyse globale d'écoulements pariétaux en régime subsonique." Thesis, Paris, ENSAM, 2015. http://www.theses.fr/2015ENAM0026/document.
Full textIn open flows context, there are generally two types of dynamic : oscillators, such as cylinder flow, exhibit a well defined frequency insensitive to external perturbations (intrinsic dynamics) and noise amplifiers, such as boundary layers, jets or in some cases the separated flows, which are characterized by wider spectrum bands that depend essentially on the external noise (dynamic extrinsic). Previous studies have shown that separated flows are subject to self-induced oscillations of low frequency in incompressible regime. These studies have revealed links between the interaction of non-normal modes and low oscillations in an incompressible boundary-layer separation and it will be to establish the validity of this interpretation in a compressible regime. In this regard, non-reflecting boundary conditions have been developed to solve the eigenvalue problem formed by linearised Navier-Stokes equations. An absorbing region known as Perfectly Matched Layer has been implemented in order to damp acoustic perturbations which are generated when the compressibility of the flow is considered. A multi-domain approach using spectral collocation discretisation has also been developed in order to study the influence of this absorbing region on the stability analysis of an open cavity flow which is known to generate acoustic perturbations. Finally, we focused on separated boundary layer induced by a bump geometry in order to understand what are the effects of compressibility on the bidimensional low frequency phenomenon and also on transverse instabilities which are known to be unstable for a lots of separated flows
Nazaikinskii, Vladimir, Anton Savin, Bert-Wolfgang Schulze, and Boris Sternin. "Elliptic theory on manifolds with nonisolated singularities : III. The spectral flow of families of conormal symbols." Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2008/2638/.
Full textMählmann, Stefan [Verfasser]. "Spectral Simulation of Leading-Edge Receptivity in Supersonic Flow over a Blunt Flat Plate / Stefan Mählmann." Aachen : Shaker, 2005. http://d-nb.info/1186580534/34.
Full textBuggisch, Lukas Werner [Verfasser], and Johannes [Akademischer Betreuer] Ebert. "The spectral flow theorem for families of twisted Dirac operators / Lukas Werner Buggisch ; Betreuer: Johannes Ebert." Münster : Universitäts- und Landesbibliothek Münster, 2019. http://d-nb.info/1190724960/34.
Full textBouzarth, Elizabeth L. Minion Michael L. "Regularized singularities and spectral deferred correction methods a mathematical study of numerically modeling Stokes fluid flow /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1917.
Full textTitle from electronic title page (viewed Dec. 11, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Mathematics." Discipline: Mathematics; Department/School: Mathematics.
Graça, Cristo dos Santos Lopes Ruano Maria da. "Investigation of real-time spectral analysis techniques for use with pulsed ultrasonic Doppler blood flow detectors." Thesis, Bangor University, 1992. https://research.bangor.ac.uk/portal/en/theses/investigation-of-realtime-spectral-analysis-techniques-for-use-with-pulsed-ultrasonic-doppler-blood-flow-detectors(f184d2a8-bde7-492a-b487-438704d3ea04).html.
Full textVadsola, Mayank. "High-Order Spectral Element Method Simulation of Flow Past a 30P30N Three-Element High Lift Wing." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40964.
Full textNath, Subhra K. "Spectral estimates and flow characteristics from non-uniformly sampled LDV data in a turbulent junction vortex." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54395.
Full textPh. D.
Mekonnen, Muluneh Admass. "Modeling flow and sediment transport in water bodies and watersheds." Doctoral thesis, KTH, Vattendragsteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4703.
Full textQC 20100827
Dao, Xuan Quy. "Fluid flow control by visual servoing." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S053/document.
Full textThe visual servoing control approach is formulated for the flow control of the plane Poiseuille flow. Generally, the flow control can lead the flow from its current state to a desired state. In transition to turbulence, the growth of kinetic energy density can lead the flow to turbulence. Moreover, the drag reduction is a potential application in the engineering applications. Therefore, this thesis aims to minimize the kinetic energy density and the skin friction drag. The governing equations of the plane Poiseuille flow are modeled to a standard form in the automatic control. More precisely, the partial differential equations of the plane Poiseuille flow are transformed to a state space representation by using the spectral method. The streamwise and spanwise directions are discretized based on the Fourier series while the wall-normal direction is discretized based on the Chebyshev polynomials. The state vector involves the wall-normal velocity and vorticity. The control signals depend on the inhomogeneous Dirichlet boundary conditions which correspond to blowing/suction boundary control. The number of independent control signals is called the number of the degree of freedom. Moreover, the skin-friction drag and the kinetic energy density are modeled as a function of the state vector. The goal is to minimize both the skin-friction drag and the kinetic energy density by appropriate methods. The partitioned visual servoing control is used to minimize, simultaneously, the skin-friction drag and the kinetic energy density with two degrees of freedom. As a result, the behavior of the skin-friction drag monotonically decreases in time. However, the behavior of the kinetic energy density does not monotonically decrease in time, the similar results from the other methods such as: PID and LQR controls. Therefore, the number of the degree of freedom increases, which leads to the improvement of the kinetic energy density. In addition, when the number of the degree of freedom equals the number of state vector, the kinetic energy density monotonically decreases in time by using the visual servoing control. The dimension of linearized plane Poiseuille flow is large, therefore, we need to reduce the order of controller. We demonstrate that the control law based on a mode reduction can be applied for the full system. Moreover, the kinetic energy density almost will monotonically decreases in time even using two degrees of freedom when the visual servoing control is designed based on the model order reduction
Liefvendahl, Mattias. "Stability results for viscous shock waves and plane Couette flow." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3241.
Full textNazaikinskii, Vladimir, Anton Savin, Bert-Wolfgang Schulze, and Boris Sternin. "Differential operators on manifolds with singularities : analysis and topology : Chapter 3: Eta invariant and the spectral flow." Universität Potsdam, 2003. http://opus.kobv.de/ubp/volltexte/2008/2659/.
Full textCardoso, Jose Carlos Silva. "Investigation and implementation of real-time spectral estimation techniques for use with pulsed Doppler blood flow detectors." Thesis, Bangor University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389743.
Full textMarklund, Lars. "Topographic Control of Groundwater Flow." Doctoral thesis, KTH, Mark- och vattenteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11153.
Full textGravitationen är den mest betydelsefulla drivkraften för grundvattenströmning. Topografin och geologin fördelar vattnets potentiella energi i landskapet. Grundvattenytans läge definierar vattnets potentiella energi, vilket är ett randvillkor för grundvattnets strömningsfält. I humida områden med en relativt tät berggrund och tillräckligt tunna jordlager, följer grundvattenytan landskapets topografi. Därav följer att grundvattenströmningen är styrd av topografin i dessa områden. I denna avhandling belyser jag den flerskaliga topografistyrda grundvattenströmningen. Min målsättning har varit att kvantitativt bestämma grundvattenströmningens rumsliga fördelning samt att undersöka hur olika geologiska parametrar påverkar grundvattencirkulationen. Jag har använt såväl numeriska modeller som analytiska lösningar, för att undersöka hur topografin styr grundvattenströmningen. De numeriska modellerna är mer komplexa än de analytiska lösningarna och kan därför användas för att undersöka betydelserna av olika förenklingar som finns i de analytiska lösningarna. De analytiska lösningarna är baserade på spektralanalys av topografin, samt superponering av enhetslösningar, där varje enhetslösning beskriver hur en specifik topografisk skala påverkar grundvattnets strömningsfält. Detta är ett effektivt tillvägagångssätt för att undersöka flerskaliga effekter av topografin, eftersom påverkan av varje enskild topografisk skala kan studeras separat. Resultaten som presenteras indikerar att topografin är fraktal och att den ger upphov till cirkulationsceller av varierande storlek som även dessa är av en fraktal natur. Denna grundläggande fördelning i grundvattnets strömningsfält ger upphov till att grundvattnets uppehållstid i marken följer ett självlikformigt mönster och kan förklara uppmätta tidsvariationer av lösta ämnens koncentrationer i vattendrag efter regn. Geologiska trender påverkar hur grundvattenströmningen styrs av topografin. De exakta lösningar som presenteras här, beskriver hur geologiska lager samt djupavtagande och anisotropisk hydraulisk konduktivitet påvekar grundvattnets strömning. Exempelvis är betydelsen av mindre topografiska skalor viktigare i områden med kvartära avlagringar och en berggrund med djupavtagande konduktivitet, än i områden med homogen bergrund utan kvartära avlagringar. Dessutom är en större andel strömmande vatten belägen närmare markytan i de förstnämnda områdena.
QC 20100802
Dines, Nicoleta, X. Liu, and Bert-Wolfgang Schulze. "Edge quantisation of elliptic operators." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2008/2683/.
Full textLi, Zhaobin. "Two-phase spectral wave explicit Navier-Stokes equations method for wave-structure interactions." Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0041/document.
Full textThis thesis proposes an efficient algorithm for simulating wave-structure interaction with two-phase Computational Fluid Dynamics (CFD) solvers. The algorithm is based on the coupling of potential wave theory and two phase Navier-Stokes equations. It is an extension of the Spectral Wave Explicit Navier-Stokes Equations (SWENSE) method for generalized two-phase CFD solvers with interface capturing techniques. In this algorithm, the total solution isdecomposed into an incident and acomplementary component. The incident solution is explicitly obtained with spectral wave models based on potential flow theory; only the complementary solution is solved with CFD solvers, representing the influence of the structure on the incident waves. The decomposition ensures the accuracy of the incident wave’s kinematics regardless of the mesh in CFD solvers. A significant reduction of the mesh size is expected in typical wave structure interaction problems. The governing equations are given in three forms: the conservative form, the non conservative form, and the Ghost of Fluid Method (GFM) form. The three sets of governing equations are implemented in OpenFOAM and validated by a series of wave-structure interaction cases. An efficient interpolation technique to map the irregular wave solution from a Higher-Order Spectral (HOS) Method onto the CFD grid is also proposed
Komminaho, Jukka. "Direct numerical simulation of turbulent flow in plane and cylindrical geometries." Doctoral thesis, Stockholm, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3054.
Full textPiatkowski, Stephan-Marian [Verfasser], and Peter [Akademischer Betreuer] Bastian. "A Spectral Discontinuous Galerkin method for incompressible flow with Applications to turbulence / Stephan-Marian Piatkowski ; Betreuer: Peter Bastian." Heidelberg : Universitätsbibliothek Heidelberg, 2019. http://d-nb.info/1191760529/34.
Full textRahimian, Abtin. "Parallel algorithms for direct blood flow simulations." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43611.
Full textMcKernan, John. "Control of plane poiseuille flow : a theoretical and computational investigation." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1431.
Full textZhu, Lailai. "Simulation of individual cells in flow." Doctoral thesis, KTH, Stabilitet, Transition, Kontroll, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142557.
Full textQC 20140313
Reich, Wieland. "Spectral, Combinatorial, and Probabilistic Methods in Analyzing and Visualizing Vector Fields and Their Associated Flows." Doctoral thesis, Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-222643.
Full text