Recent Submissions

  • Passivity-preserving splitting methods for rigid body systems 

    Celledoni, Elena; Høiseth, Eirik Hoel; Ramzina, Nataliya (Journal article, 2018)
    A rigid body model for the dynamics of a marine vessel, used in simulations of offshore pipe-lay operations, gives rise to a set of ordinary differential equations with controls. The system is input–output passive. We ...
  • Adaptive energy preserving methods for partial differential equations 

    Eidnes, Sølve; Owren, Brynjulf; Ringholm, Torbjørn (Journal article; Peer reviewed, 2017)
    A framework for constructing integral preserving numerical schemes for time-dependent partial differential equations on non-uniform grids is presented. The approach can be used with both finite difference and partition of ...
  • Long-term variation in numbers and biomass of silver eels being produced in two European river systems 

    Poole, W. Russell; Diserud, Ola Håvard; Thorstad, Eva Bonsak; Durif, Caroline; Dolan, Conor; Sandlund, Odd Terje; Bergesen, Knut Aanestad; Rogan, Gerard; Kelly, Sean D.; Vøllestad, Leif Asbjørn (Journal article; Peer reviewed, 2018)
    The European eel (Anguilla anguilla) population has been in decline at least since the 1960s and reliable regional information, particularly on the spawner production and escapement (i.e. the silver eel life stage), is a ...
  • On the similarities and differences between Classical Hierarchical, Truncated Hierarchical and LR B-splines 

    Johannessen, Kjetil Andre; Remonato, Filippo; Kvamsdal, Trond (Journal article; Peer reviewed, 2015)
    Smooth spline functions such as B-splines and NURBS are already an established technology in the field of computer-aided design (CAD) and have in recent years been given a lot of attention from the computer-aided engineering ...
  • Divergence-conforming discretization for Stokes problem on locally refined meshes using LR B-splines 

    Johannessen, Kjetil Andre; Kumar, Mukesh; Kvamsdal, Trond (Journal article; Peer reviewed, 2015)
    To solve the incompressible flow problems using isogeometric analysis, the div-compatible spline spaces were originally introduced by Buffa et al. (2011), and later developed by Evans (2011). In this paper, we extend the ...
  • Demonstrating the impact of bidirectional coupling on the performance of an ocean-met model 

    Rasheed, Adil; Tabib, Mandar; Süld, Jakob Kristoffer; Kristiansen, Jørn; Kvamsdal, Trond (Journal article; Peer reviewed, 2017)
    The mass, momentum and energy fluxes between the atmosphere and ocean surface depend on the state of the ocean surface. The fluxes in turn can significantly alter the nature of the marine boundary layer and the state of ...
  • Numerical Analysis of NREL 5MW Wind Turbine: A Study Towards a Better Understanding of Wake Characteristic and Torque Generation Mechanism 

    Siddiqui, Muhammad Salman; Rasheed, Adil; Tabib, Mandar; Kvamsdal, Trond (Journal article; Peer reviewed, 2016)
    With the increased feasibility of harvesting offshore wind energy, scale of wind turbines is growing rapidly and there is a trend towards clustering together higher number of turbines in order to harvest maximum yield and ...
  • Investigation of the impact of wakes and stratification on the performance of an onshore wind farm 

    Tabib, Mandar; Rasheed, Adil; Kvamsdal, Trond (Journal article; Peer reviewed, 2015)
    This work investigates the effects of wakes and stratification on the performance of turbines operating in the Bessaker wind farm. The wind farm is located in a highly complex terrain. Most dominant wind directions recorded ...
  • Front Tracking for Hyperbolic Conservation Laws 

    Holden, Helge; Risebro, Nils Henrik (Applied mathematical sciences;, Book, 2015)
  • Periodic Orbits for Transcendental Hénon Maps 

    Nguyen, Huu Tai Terje (Master thesis, 2018)
    This master thesis deals with periodic points of transcendental Hénon maps, a subject in complex dynamics. In particular, we investigate the existence of periodic points and the discreteness of the set of $k$-periodic ...
  • Algebraic thinking 

    Hodgen, Jeremy; Oldenburg, Reinhard; Strømskag, Heidi (Chapter, 2018)
    Algebra is one of the most extensively researched areas in mathematics education. Over the past 40 years, many researchers have addressed the problems associated with the learning and teaching of algebra in school and ...
  • Some Improved Estimates in the Dirichlet Divisor Problem from Bourgain's Exponent Pair 

    Teklehaymanot, Nigus Girmay (Master thesis, 2018)
    The thesis work is a survey of recent developments on the famous error terms in the Dirichlet divisor problem. We consider the power moments of the Riemann zeta-function in the critical strip and we managed to obtain some ...
  • On distributional solutions of local and nonlocal problems of porous medium type 

    del Teso Mendez, Felix; Endal, Jørgen; Jakobsen, Espen Robstad (Journal article; Peer reviewed, 2017)
    We present a theory of well-posedness and a priori estimates for bounded distributional (or very weak) solutions of ∂tu − L σ,µ[ϕ(u)] = g(x, t) in R N (0.1) × (0, T ), where ϕ is merely continuous and nondecreasing and L ...
  • Split-plot designs for multistage Experimentation 

    Tyssedal, John Sølve; Kulahci, Murat (Journal article; Peer reviewed, 2017)
    Most of today’s complex systems and processes involve several stages through which input or the raw material has to go before the final product is obtained. Also in many cases factors at different stages interact. Therefore, ...
  • Shape analysis on lie groups and homogeneous spaces 

    Celledoni, Elena; Eidnes, Sølve; Eslitzbichler, Markus; Schmeding, Alexander (Journal article, 2017)
    In this paper we are concerned with the approach to shape analysis based on the so called Square Root Velocity Transform (SRVT). We propose a generalisation of the SRVT from Euclidean spaces to shape spaces of curves on ...
  • Headache following head injury: a population-based longitudinal cohort study (HUNT) 

    Nordhaug, Lena Hoem; Hagen, Knut; Vik, Anne; Stovner, Lars Jacob; Follestad, Turid; Pedersen, Torunn; Gravdahl, Gøril Bruvik; Linde, Mattias (Journal article; Peer reviewed, 2018)
    Background Headache is the most frequent symptom following head injury, but long-term follow-up of headache after head injury entails methodological challenges. In a population-based cohort study, we explored whether ...
  • Fabrication of a scaled MgB2 racetrack demonstrator pole for a 10 MW direct drive wind turbine generator 

    Magnusson, Niklas; Eliassen, J. C.; Abrahamsen, Asger B; Hellesø, Svein Magne; Runde, Magne; Nysveen, Arne; Moslått, Lars-Erik; Bjerkli, Jarle; King, Patrick (Journal article; Peer reviewed, 2018)
    Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in ...
  • On nonlocal dispersive equations and water waves 

    Arnesen, Mathias Nikolai (Doctoral theses at NTNU;2018:84, Doctoral thesis, 2018)
  • Isogeometric Analysis of Acoustic Scattering using Infinite Elements 

    Venås, Jon Vegard; Kvamsdal, Trond; Jenserud, Trond (Journal article; Peer reviewed, 2018)
    Isogeometric analysis (IGA) has proven to be an improvement on the classical finite element method (FEM) in several fields, including structural mechanics and fluid dynamics. In this paper, the performance of IGA coupled ...
  • Simulation-Regression Approximations for Value of Information Analysis of Geophysical Data 

    Eidsvik, Jo; Dutta, Geetartha; Mukerji, Tapan; Bhattacharjya, Debarun (Journal article, 2017)
    Value of information analysis is useful for helping a decision maker evaluate the benefits of acquiring or processing additional data. Such analysis is particularly beneficial in the petroleum industry, where information ...

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