doc. RNDr. Libor Čermák, CSc.

E-mail:   cermak@fme.vutbr.cz 
WWW:   http://www.mat.fme.vutbr.cz/home/cermakl
Dept.:   Institute of Mathematics
Dept. of Mathematical Analysis
Position:   Associate Professor
Room:   A3/712
Phone:   +420 54114 2717

1269

Education and academic qualification

  • 1973, graduated mathematician, Masaryk university Brno, Faculty of science, branch mathematics
  • 1975, RNDr., Masaryk university Brno, Faculty of science, branch numerical methods
  • 1982, CSc., VUT Brno, branch mathematics and physics sciences
  • 1987, doc., VUT Brno, branch numerical methods

Career overview

  • 1973-1983, specialist worker, OVC VUT Brno
  • 1983-1990, research worker, OVC VUT Brno
  • 1990-to date, docent, Institute of mathematics, FSI VUT Brno

Pedagogic activities

  • BSC study programme: Mathematics, Numerical methods
  • MSC study programme, study branch Mathematical Engineering: Numerical methods, Mathematical methods in fluid dynamics
  • MSC Thesis: Numerical methods solving various technical problems
  • Doctoral study programme: Numerical methods

Scientific activities

  • Numerical solution of partial differential equations, especially the finite element method, applied to various engineering problems.

Projects

  • Grant Agency of the Czech Republic: 201/95/1557 Mathematical Modelling of Engineering problems (1995-96, co-worker)
  • Grant Agency of the Czech Republic: 201/97/0153 Mathematical Modelling of some nonlinear problems in Continuum Mechanics (1997-99, co-worker)
  • Grant Agency of the Czech Republic: 201/00/0557 Mathematical modelling of some problems in Continuum mechanics (2000-2002, co-worker)

Supervised courses:

Publications:

  • BAJKO, J.; ČERMÁK, L.; JÍCHA, M.:
    High order finite point method for the solution to the sound propagation problems,
    COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, Vol.280, (2014), No.10, pp.157-175, ISSN 0045-7825, Elsevier
    journal article
  • BAJKO, J.; ČERMÁK, L.; JÍCHA, M.; HARTMANN, M.:
    Meshfree method for computational aeroacoustics using LEE for the solution of noise propagation,
    Particle-Based Methods III. Fundamentals and Applications, pp.752-763, ISBN 978-84-941531-8-1, (2013), Artes Gráficas Torres S.A.
    conference paper
    akce: III International Conference on Particle-Based Methods. Fundamentals and Applications, Particles 2013., Stuttgart, 18.09.2013-20.09.2013
  • ZAPOMĚL, J.; FERFECKI, P.; ČERMÁK, L.:
    A computational method for determination of a frequency response characteristic of flexibly supported rigid rotors attenuated by short magnetorheological squeeze film dampers,
    Applied andComputational Mechanics, Vol.5, (2011), No.1, pp.101-110, ISSN 1802-680X
    journal article
  • POCHYLÝ, F.; ČERMÁK, L.; RUDOLF, P.; HABÁN, V.; KOUTNÍK, J.:
    Assessment of the steady swirling flow stability using amplitude-frequency characteristic,
    Proceedings of the 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems - part I., pp.25-34, ISBN 978-80-214-3947-4, (2009)
    conference paper
    akce: 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, 14.10.2009-16.10.2009
  • ZAPOMĚL, J.; ČERMÁK, L.; POCHYLÝ, F.:
    A computational investigation of vibration of stationary and rotating structures submerged in a liquid,
    Applied andComputational Mechanics, pp.177-186, ISSN 1802-680X
    journal article

List of publications at Portal BUT

Abstracts of most important papers:

  • ZAPOMĚL, J.; FERFECKI, P.; ČERMÁK, L.:
    A computational method for determination of a frequency response characteristic of flexibly supported rigid rotors attenuated by short magnetorheological squeeze film dampers,
    Applied andComputational Mechanics, Vol.5, (2011), No.1, pp.101-110, ISSN 1802-680X
    journal article

    Lateral vibration of rotors can be significantly reduced by inserting the damping elements between the shaft and the casing. The theoretical analysis, confirmed by computational simulations, shows that to achieve the optimum compromise between attenuation of the oscillation amplitude and magnitude of the forces transmitted through the coupling elements between the rotor and the stationary part, the damping effect must be controllable. For this purpose, the squeeze film dampers lubricated by magnetorheological fluid can be applied. The damping effect is controlled by the change of intensity of the magnetic field in the lubricating film. This article presents a procedure developed for investigation of the steady state response of rigid rotors coupled with the casing by flexible elements and short magnetorheological dampers. Their lateral vibration is governed by nonlinear (due to the damping forces) equations of motion. The steady state solution is obtained by application of a collocation method, which arrives at solving a set of nonlinear algebraic equations. The pressure distribution in the oil film is described by a Reynolds equation modified for the case of short dampers and Bingham fluid. Components of the damping force are calculated by integration of the pressure distribution around the circumference and along the length of the damper. The developed procedure makes possible to determine the steady state response of rotors excited by their unbalance, to determine magnitude of the forces transmitted through the coupling elements in the supports into the stationary part and is intended for proposing the control of the damping effect to achieve optimum performance of the dampers.
  • Pochylý František, Malenovský Eduard, Čermák Libor:
    Analysis of the dynamic behavior of squeeze film dampers using a finite element method

    The dynamic behavior of hydrodynamic dampers was analyzed. Our solution is based on the Lagrange transformation of Navier Stokes and continuity equations, assuming small vibrations of the structure. A real compressible liquid with a new model for the bulk modulus of the second viscosity was assumed. The numerical solution is based on a finite element method, and new equations of hydrodynamics corresponding to equations of the dynamics of elastic structure were derived. For the detailed analysis of long squeeze film dampers (plane deformation) a custom MATLAB program was developed. The analogy of hydrodynamics and dynamics of elastic structure allowed the comparison of the results for the displacements and pressure field with those obtained from ANSYS.
  • POCHYLÝ, F.; RUDOLF, P.; HABÁN, V.; ČERMÁK, L.:
    A note on influence of velocity field on stability of the flow in axisymmetric domain with focus on origin of the cavitating vortex rope,
    Proceedings of the 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems - part II, pp.625-631, ISBN 978-80-214-3947-4, (2009)
    conference paper
    akce: 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, 14.10.2009-16.10.2009

    Swirling flow is very susceptible to instabilities, which often manifested by appearance of concentrated vertical structure - vortex rope. Basic analysis of the swirling fluid flow in a cylindrical domain is presented in the paper. Aim of the paper is to show relations between velocity components and coupling between velocity and pressure field leading to a cavitating vortex rope.
  • POCHYLÝ, F.; ČERMÁK, L.; RUDOLF, P.; HABÁN, V.; KOUTNÍK, J.:
    Assessment of the steady swirling flow stability using amplitude-frequency characteristic,
    Proceedings of the 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems - part I., pp.25-34, ISBN 978-80-214-3947-4, (2009)
    conference paper
    akce: 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, 14.10.2009-16.10.2009

    Paper presents description of the methodology for assessing swirling flow stability. In contrast to current approach, CFD is only used supplying of the steady velocity field. Rest of the analysis is done by solution of the eigen value problem, which is formed by linearized Euler equations. Numerical procedure based on spectral element method in combination with forced oscillations solution enables to determine a set of eigen frequencies of the swirling liquid. Presented method is a fast tool to assess stability of the draft tube flow for different inlet velocity boundary conditions or different draft tube shapes.
  • ZAPOMĚL, J.; ČERMÁK, L.; POCHYLÝ, F.:
    A computational investigation of vibration of stationary and rotating structures submerged in a liquid,
    Applied andComputational Mechanics, pp.177-186, ISSN 1802-680X
    journal article

    The article is devoted to the numerical modelling of the structure-fluid interaction of a solid body submerged in a fluid. It is supposed that the submerged body is absolutely rigid and that the pressure distribution in the liquid can be described by the Laplace euquation in 2D domain.The space discretization in the liquid is carried out in two ways. The first approach is based on the finite element method in the physical domain with a moving boundary (between body and liquid). The second method transforms the physical domain with moving boundary to the fixed reference domain and the transformed Laplace problem is then solved by the finite difference method. The time discretization is realized by the backward Euler method. The applicability of both approaches is verified by numerical tests.