C. Bommaraju

Technical University Darmstadt, Darmstadt, Hesse, Germany

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Publications (13)1.07 Total impact

  • C. Bommaraju
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    ABSTRACT: In this paper, an approach to extract the scattering parameters using upwind flux finite volume time domain methods is explained. The approach does not alter the core finite volume time domain algorithm. This scheme can be extended to discontinuous Galerkin finite element methods.
    Applied Electromagnetics Conference (AEMC), 2011 IEEE; 01/2011
  • C. Bommaraju
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    ABSTRACT: In this paper, the scattering parameters computed using upwind flux finite volume time domain methods of an inhomogeneous coaxial cable with high contrast of materials are furnished. A convergence study has been performed on the accuracy of the obtained scattering parameters using finite volume methods in addition to the finite integration technique.
    Applied Electromagnetics Conference (AEMC), 2011 IEEE; 01/2011
  • C. Bommaraju
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    ABSTRACT: In this paper, the finite volume time domain semi-discrete formulation, discrete in space and continuous in time, is presented. To turn this into a discrete system of equations, various time marching schemes are employed. An investigation is carried out on the stability of finite volume time domain methods for both central and upwind fluxes, employing these time marching schemes.
    Applied Electromagnetics Conference (AEMC), 2011 IEEE; 01/2011
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    C. Bommaraju, W. Ackermann, T. Weiland
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    ABSTRACT: In this paper, the finite volume time domain (FVTD) semi-discrete formulation, discrete in the space and continuous in the time, is derived for the electromagnetic field simulation, starting from the Maxwell's equations. The time marching schemes that can be employed to turn this into discrete system of equations are presented. The discrete formulation is used to explain variations in FVTD methods e.g., methods which differ in spatial approximation. For a given problem, numerical methods anticipate the convergence of the solutions towards the reference (analytical) solution as the grid is refined. The convergence order for various FVTD methods is presented in different scenarios and compared with that of finite integration technique (FIT) and finite element method (FEM).
    Applied Electromagnetics Conference (AEMC), 2009; 01/2010
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    C. Bommaraju, W. Ackermann, T. Weiland
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    ABSTRACT: Adapted from 'Computational Fluid Dynamics', Finite Volume Time Domain (FVTD) method is becoming increasingly popular in 'Computational Electromagnetics'. The focus of this paper is on the convergence analysis of different FVTD methods on tetrahedral and hexahedral meshes. Other aspects like implementation techniques, CPU time and memory are also furnished.
    Computational Electromagnetics in Time-Domain, 2007. CEM-TD 2007. Workshop on; 11/2007
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    C. Bommaraju, R. Marklein
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    ABSTRACT: The dispersion relation and convergence of a novel (2,2) modified finite-difference time-domain (MFDTD) method, which has fourth order convergence and excellent broadband characteristics, are presented. Accuracy of MFDTD is compared with that of standard FDTD and Fang (4,4) FDTD. The Convergence characteristics of the MFDTD and the FDTD are also furnished. We have presented MFDTD in 2-D in CEM-TD 2005. Here we extend MFDTD to 3-D.
    Computational Electromagnetics in Time-Domain, 2007. CEM-TD 2007. Workshop on; 11/2007
  • Chakrapani Bommaraju, Rene Marklein, Rolf Schuhmann, Thomas Weiland
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    ABSTRACT: The dispersion relation and the convergence of a modified finite-difference time-domain scheme (MFDTD), which has fourth-order convergence and excellent broadband characteristics, are presented. The accuracy of several low-dispersion finite-difference time-domain schemes in 2-D is compared with that of the MFDTD, via direct evaluation of the dispersion relation. Convergence of the FDTD and the MFDTD in 2-D are also examined. Copyright © 2006 John Wiley & Sons, Ltd.
    International Journal of Numerical Modelling Electronic Networks Devices and Fields 01/2007; 20(1–2):17-33. · 0.54 Impact Factor
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    Chakrapani Bommaraju, Rene Marklein, Rolf Schuhmann, Thomas Weiland
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    ABSTRACT: The dispersion relation and the convergence of a modified finite-difference time-domain scheme (MFDTD), which has fourth-order convergence and excellent broadband characteristics, are presented. The accuracy of several low-dispersion finite-difference time-domain schemes in 2-D is compared with that of the MFDTD, via direct evaluation of the dispersion relation. Convergence of the FDTD and the MFDTD in 2-D are also examined. Copyright © 2006 John Wiley & Sons, Ltd.
    International Journal of Numerical Modelling Electronic Networks Devices and Fields 12/2006; 20(1‐2):17 - 33. · 0.54 Impact Factor
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    ABSTRACT: A novel optimally accurate second-order finite-difference time-domain method was previously presented for the 1D and 2D cases. In this paper that approach is extended to the 3D case. The dispersion relation and convergence of a modified finite-difference time-domain method (MFDTD) which has fourth order convergence and excellent broadband characteristics, are presented. The accuracy of FDTD, Fang(4,4) are compared with that of the MFDTD, via direct evaluation of the dispersion relation. Convergence of the FDTD and the MFDTD are also examined
    01/2006;
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    Bommaraju C, Marklein R, P. K. Chinta
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    ABSTRACT: Numerical methods are extremely useful in solving real-life problems with complex materials and geometries. However, numerical methods in the time domain suffer from artificial numerical dispersion. Standard numerical techniques which are second-order in space and time, like the conventional Finite Difference 3-point (FD3) method, Finite-Difference Time-Domain (FDTD) method, and Finite Integration Technique (FIT) provide estimates of the error of discretized numerical operators rather than the error of the numerical solutions computed using these operators. Here optimally accurate time-domain FD operators which are second-order in time as well as in space are derived. Optimal accuracy means the greatest attainable accuracy for a particular type of scheme, e.g., second-order FD, for some particular grid spacing. The modified operators lead to an implicit scheme. Using the first order Born approximation, this implicit scheme is transformed into a two step explicit scheme, namely predictor-corrector scheme. The stability condition (maximum time step for a given spatial grid interval) for the various modified schemes is roughly equal to that for the corresponding conventional scheme. The modified FD scheme (FDM) attains reduction of numerical dispersion almost by a factor of 40 in 1-D case, compared to the FD3, FDTD, and FIT. The CPU time for the FDM scheme is twice of that required by the FD3 method. The simulated synthetic data for a 2-D P-SV (elastodynamics) problem computed using the modified scheme are 30 times more accurate than synthetics computed using a conventional scheme, at a cost of only 3.5 times as much CPU time. The FDM is of particular interest in the modeling of large scale (spatial dimension is more or equal to one thousand wave lengths or observation time interval is very high compared to reference time step) wave propagation and scattering problems, for instance, in ultrasonic antenna and synthetic scattering data modeling for Non-Destructive Testing (NDT) applications, where other standard numerical methods fail due to numerical dispersion effects. The possibility of extending this method to staggered grid approach is also discussed. The numerical FD3, FDTD, FIT, and FDM results are compared against analytical solutions.
    Advances in Radio Science 01/2005;
  • C. Bommaraju, R. Schuhmann, T. Weiland
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    ABSTRACT: Not Available
    Computational Electromagnetics in Time-Domain, 2005. CEM-TD 2005. Workshop on; 01/2005
  • C. Bommaraju, R. Marklein
    [Show abstract] [Hide abstract]
    ABSTRACT: Numerical methods are extremely useful in solving real-life problems with complex materials and geometries. However, numerical methods in the time domain stiffer from artificial numerical dispersion. Standard numerical techniques which are second-order in space and time, like the conventional finite-difference three point (FD3) method, finite-difference time-domain (FDTD) method, and finite integration technique (FIT), provide estimates of the error of discretized numerical operators rather than the error of the numerical solutions computed using these operators. Here, optimally accurate time-domain (TD) finite-difference (FD) operators which are second-order in time as well as in space are derived. Optimal accuracy means the greatest attainable accuracy for a particular type of scheme, e.g., second-order FD, for some particular grid spacing. The modified FD scheme - FD modified: FDM - presented here attains reduction of numerical dispersion almost by a factor of 40 compared to the FD3, FDTD, and FIT. The CPU time for the FDM scheme is twice of that required by FD3 method. The modified operators lead to an implicit scheme, which is approximated by a predictor-corrector scheme yielding a two step explicit scheme. The possibility of extending this method to a staggered grid approach is also presented. Finally the comparison between analytical solution, FDTD/FIT method, FD3 method and FDM scheme with simulation results is depicted. Further examples are given in the presentation.
    Antennas and Propagation Society International Symposium, 2004. IEEE; 07/2004
  • Source
    Chakrapani Bommaraju, Rene Marklein, Rolf Schuhmann, Thomas Weiland
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    ABSTRACT: The dispersion relation and the convergence of a modified finite-difference time-domain scheme (MFDTD), which has fourth order convergence and excellent broadband characteristics, are presented. The accuracy of several low-dispersion finite-difference time-domain schemes in 2-D is compared with that of the MFDTD, via direct evaluation of the dispersion relation. Convergence of the FDTD and the MFDTD in 2-D are also examined.
    J. Numer. Model. 01/2000; 00:1-6.

Publication Stats

7 Citations
1.07 Total Impact Points

Institutions

  • 2000–2010
    • Technical University Darmstadt
      • • Institut für Kernphysik
      • • Insitute of Computational Electromagnetics
      Darmstadt, Hesse, Germany
  • 2000–2004
    • Universität Kassel
      Cassel, Hesse, Germany