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  1. Article

    Open Access

    On the well-posedness of the Cauchy problem for the two-component peakon system in \(C^k\cap W^{k,1}\)

    This study focuses on the Cauchy problem associated with the two-component peakon system featuring a cubic nonlinearity, constrained to the class ...

    K. H. Karlsen, Ya. Rybalko in Zeitschrift für angewandte Mathematik und Physik (2024)

  2. Article

    Open Access

    A nonlocal Lagrangian traffic flow model and the zero-filter limit

    In this study, we start from a Follow-the-Leaders model for traffic flow that is based on a weighted harmonic mean (in Lagrangian coordinates) of the downstream car density. This results in a nonlocal Lagrangi...

    G. M. Coclite, K. H. Karlsen, N. H. Risebro in Zeitschrift für angewandte Mathematik und … (2024)

  3. No Access

    Article

    Numerical methods for conservation laws with rough flux

    Finite volume methods are proposed for computing approximate pathwise entropy/kinetic solutions to conservation laws with flux functions driven by low-regularity paths. For a convex flux, it is demonstrated th...

    H. Hoel, K. H. Karlsen, N. H. Risebro in Stochastics and Partial Differential Equa… (2020)

  4. No Access

    Chapter and Conference Paper

    Some Wellposedness Results for the Ostrovsky–Hunter Equation

    The Ostrovsky-Hunter equation provides a model for small-amplitude long waves in a rotating fluid of finite depth. It is a nonlinear evolution equation. In this paper the welposedness of the Cauchy problem and...

    G. M. Coclite, L. di Ruvo, K. H. Karlsen in Hyperbolic Conservation Laws and Related A… (2014)

  5. No Access

    Article

    An error estimate for the finite difference approximation to degenerate convection–diffusion equations

    We consider semi-discrete first-order finite difference schemes for a nonlinear degenerate convection–diffusion equations in one space dimension, and prove an L 1 error estimate. Precisely, we sho...

    K. H. Karlsen, U. Koley, N. H. Risebro in Numerische Mathematik (2012)

  6. No Access

    Article

    Identification of diffusion parameters in a nonlinear convection–diffusion equation using the augmented Lagrangian method

    Numerical identification of diffusion parameters in a nonlinear convection–diffusion equation is studied. This partial differential equation arises as the saturation equation in the fractional flow formulation...

    T. K. Nilssen, K. H. Karlsen, T. Mannseth, X.-C. Tai in Computational Geosciences (2009)

  7. No Access

    Article

    A family of numerical schemes for kinematic flows with discontinuous flux

    Multiphase flows of suspensions and emulsions are frequently approximated by spatially one-dimensional kinematic models, in which the velocity of each species of the disperse phase is an explicitly given funct...

    R. Bürger, A. García, K. H. Karlsen, J. D. Towers in Journal of Engineering Mathematics (2008)

  8. No Access

    Chapter and Conference Paper

    Global Weak Solutions for a Shallow Water Equation

    G. M. Coclite, H. Holden, K. H. Karlsen in Hyperbolic Problems: Theory, Numerics, App… (2008)

  9. No Access

    Chapter and Conference Paper

    A Hyperbolic-Elliptic Model for Coupled Well-Porous Media Flow

    S. Evje, K. H. Karlsen in Hyperbolic Problems: Theory, Numerics, Applications (2008)

  10. No Access

    Article

    Convergence Rates for Semi-Discrete Splitting Approximations for Degenerate Parabolic Equations with Source Terms

    We study a semi-discrete splitting method for computing approximate viscosity solutions of the initial value problem for a class of nonlinear degenerate parabolic equations with source terms. It is fairly sta...

    E. R. Jakobsen, K. H. Karlsen in BIT Numerical Mathematics (2005)

  11. No Access

    Article

    Monotone difference approximations for the simulation of clarifier-thickener units

    Clarifier-thickener units treating ideal suspensions can be modeled as an initial-value problem for a nonconvex scalar conservation law whose flux depends on a vector of discontinuous parameters. This problem ...

    R. Bürger, K.H. Karlsen, N.H. Risebro in Computing and Visualization in Science (2004)

  12. No Access

    Article

    Well-posedness in BV t and convergence of a difference scheme for continuous sedimentation in ideal clarifier-thickener units

    We consider a scalar conservation law modeling the settling of particles in an ideal clarifier-thickener unit. The conservation law has a nonconvex flux which is spatially dependent on two discontinuous parame...

    R. Bürger, K.H. Karlsen, N.H Risebro, J.D. Towers in Numerische Mathematik (2004)

  13. No Access

    Chapter and Conference Paper

    Relaxation Schemes for Conservation Laws with Discontinuous Coefficients

    We study relaxation schemes for conservation laws with discontinuous coefficients, and compare these numerically with an Engquist-Osher type scheme and with a front tracking method. If the coefficients are of ...

    K. H. Karlsen, C. Klingenberg, N. H. Risebro in Hyperbolic Problems: Theory, Numerics, App… (2003)

  14. No Access

    Chapter and Conference Paper

    On a Model for Continuous Sedimentation in Vessels with Discontinuous Cross-sectional Area

    We study a clarifier-thickener unit considering that its cross-sectional area is not constant in both the clarification and the thickening zones. A mathematical model of sedimentation in such a vessel can be f...

    R. Bürger, K. H. Karlsen, N. H. Risebro in Hyperbolic Problems: Theory, Numerics, App… (2003)

  15. No Access

    Article

    Numerical Solution of the Polymer System by Front Tracking

    The paper describes the application of front tracking to the polymer system, an example of a nonstrictly hyperbolic system. Front tracking computes piecewise constant approximations based on approximate Rieman...

    V. Haugse, K. H. Karlsen, K.-A. Lie, J. R. Natvig in Transport in Porous Media (2001)

  16. No Access

    Chapter and Conference Paper

    A Continuous Dependence Result for Nonlinear Degenerate Parabolic Equations with Spatially Dependent Flux Function

    We study entropy solutions of nonlinear degenerate parabolic equations of form,where k(x) is a vector-valued function and f(u),A(u) are scalar functions. We prove a result concerning the continuous dependence ...

    S. Evje, K. H. Karlsen in Hyperbolic Problems: Theory, Numerics, Applications (2001)

  17. No Access

    Chapter and Conference Paper

    On the Convergence Rate of Operator Splitting for Weakly Coupled Systems of Hamilton-Jacobi Equations

    Assuming existence and uniqueness of bounded Lipschitz continuous viscosity solutions to the initial value problem for weakly coupled systems of Hamilton-Jacobi equations, we establish a linearL¡ã¡ãconvergence ra...

    E. R. Jakobsen, K. H. Karlsen, N. H. Risebro in Hyperbolic Problems: Theory, Numerics, App… (2001)