Edi Cahyono
Faculty of Mathematical Sciences
University of Twente
PO Box 217
7500 AE Enschede
The Netherlands
Phone : +31 53 489 3397
Fax. : +31 53 489 4833
E-mail : e.cahyono@math.utwente.nl
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PhD project

My research is part of a cooperation project (LABMATH) between MARIN (Maritime Research Institute Netherlands) in Wageningen and faculty of Mathematical Sciences, the university of Twente, both are in the Netherlands and IHL (Indonesian Hydrodynamics Laboratory) in Surabaya, and the Center of Mathematics at ITB, Indonesia.

This research mainly concerns on predicting the evolution of surface waves. The interest is in wave fields that are generated in towing tanks of hydrodynamics laboratories such as MARIN and IHL. Such tanks are typically 200 m long and 5 m deep, with waves of heights up to 10% of the depth, that are used to test models of ships and offshore structures. To test the performance of the models in operational conditions, the waves to be generated should resemble waves at seas.

Although the basic equations governing surface waves are known, they are too complicated for a direct theoretical investigation. Numerical codes based on these equations have been designed. To study the waves theoretically, however, a simpler model is desired to understand better the characteristic properties, and to generate quantitative results in a good approximation. The quantitative results obtained with an `analytical wave code' (AWC) are to be used to predict the motion of wave generators at one side of the tank from desired wave evolutions in the middle of the tank.

As model equation, a uni directional wave equation with typical quadratic nonlinearity is taken. Since the dispersive properties should be correct for the relatively short wavelengths that are of interest for the laboratories (1 to 3 times the water depth), the standard KdV (Korteweg - de Vries) equation is not suited, and has been replaced by an `improved KdV' (iKdV) that has exact dispersive properties for small waves. Then, the interest is to find (approximate) solutions of iKdV that describe the evolution of a wave field that is compatible with a prescribed desired evolution at a specified point (signal problem). Anticipating small amplitude waves, approximations are sought as series expansions in the wave height.

Publications Curriculum vitae Top

Publications:
  • E. Cahyono, E. van Groesen, E. Soewono & S. Subarinah, Genus-two solutions to the Kadomtsev-Petviashvili equation, in: Differential equations: Theory Numerics and Applications, E van Groesen E. Soewono (eds.), Kluwer Academic Publishers, 1997.

  • A. Jamalluddin, E. Cahyono, E. van Groesen & Andonowati, Wave Generation at IHL, Proceedings of International Symposium on Advanced and Aerospace Science and Engineering in Indonesia , August 31, 1998.

  • E. Cahyono, E. van Groesen & Andonowati, Predicting wave field evolutions in towing tanks, Proceedings ITB, Asia/Pacific congress on engineering computational modeling and signal processing (ECM & SP '99), November 1999.

  • E. Cahyono, M. E. Hochstenbach, J. Molenaar, W. H. A. Schilders & G. M. Terra, Velocity estimation in mixtures using tomography, Proceedings of the Thirty-ninth European Study Group with Industry, SWI 2000.

  • E. van Groesen, E. Cahyono & A. Suryanto, Uni-directional models for narrow and broad pulse propagation in second order nonlinear media, accepted for publication in Optical and Quantum Electronics.

  • E. Cahyono, E. van Groesen & Andonowati, An analytical investigation on the nonlinear evolution of bichromatic wave groups, Submitted.

PhD project Curriculum vitae Top

Curriculum vitae
  • Education:
    • PhD-project in execution in the Faculty of Mathematical Sciences, University of Twente, The Netherlands since November 1997.
    • MSc. in Mathematics. Institut Teknologi Bandung (ITB), Bandung, Indonesia, 1995
    • BSc. in Mathematics Education. IKIP Malang , Malang, Indonesia, 1992.

  • Teaching Experiences:
    • Jul 1996 - Sep 1997 at Universitas Haluoleo, Kendari, Indonesia.
    • Jan - Sep 1995 at Institut Teknologi Bandung, Bandung, Indonesia.

  • Research Experiences:
    • Nov 1995 - April 1996 Six month research training at the University of Twente, the Netherlands.
    • Jul - Sep 1996 Three month research workshop : Mathematics in Industry at ITB, Indonesia.

PhD project Publications Top