FNPT-2D is a finite element based model for Fully-Nonlinear Potential Theory. A simple, robust and fastest computational tool to estimate the fully nonlinear wave kinematics for very steep non-breaking waves.

  • X-Z plane.
  • Single fluid model.
  • Lagrangian or Semi-lagrangian method due to moving free-surface.
  • Exponentially varying mesh-size along the vertical direction.
  • Velocities captured accurately by using LSQ methods for calculating gradients of potential function.
  • 1st order, 2nd order wavemaker theory, all type of waves
  • Variable bathymetry, steep non-breaking waves
  • Moving piston-type wavemaker.

It has experimentally verified proven result for (a) Regular waves (b) irregular/random waves (c) solitary waves (d) cnoidal waves (e) Gaussian wave packets (f) focusing waves (g) long waves – pulse, N-waves (h) user defined waves (i) Sloshing.

List of a few important publication from this model

  1. Sriram, V. (2008). Finite element simulation of nonlinear free surface waves (Indian Institute of Technology Madras). PhD Thesis. 
  2. Sriram, V., Sannasiraj, S. A., & Sundar, V. (2006). Simulation of 2-D nonlinear waves using finite element method with cubic spline approximation. Journal of Fluids and Structures, 22(5), 663–681. https://doi.org/10.1016/j.jfluidstructs.2006.02.007
  3. Sriram V., Sannasiraj S.A., and Sundar V., 2006, “Numerical simulation of 2D sloshing waves due to horizontal and vertical random excitations”, Applied Ocean Research, 28(1), 19-32.
  4. Sriram, V., Sannasiraj, S. A., Sundar, V., Schlenkhoff, A., & Schlurmann, T. (2010). Quantification of phase shift in the simulation of shallow water waves. International Journal for Numerical Methods in Fluids. https://doi.org/10.1002/fld.2072
  5. Sriram, V., Schlurmann, T., & Schimmels, S. (2013). Focused Wave Evolution in Intermediate Water Depth Using First and Second Order Wave Maker Theory. The Twenty-Third International Offshore and Polar Engineering Conference. Anchorage, Alaska: International Society of Offshore and Polar Engineers.
  6. Sriram, V., Schlurmann, T., & Schimmels, S. (2015). Focused wave evolution using linear and second order wavemaker theory. Applied Ocean Research, 53, 279–296. https://doi.org/10.1016/j.apor.2015.09.007
  7. V. Sriram, I. Didenkulova, A. Sergeeva, S. Schimmels, 2016, Tsunami evolution and run-up in a large scale experimental facility, Coastal Engineering, 111, 1-12.
  8. S. Schimmels, V.Sriram, I. Didenkulova, 2016, Tsunami generation in a large scale experimental facility, Coastal Engineering, 110, 32–41
  9. H. Fernándeza, V. Sriram, S. Schimmels, H. Oumeraci, 2014, Extreme wave generation using self-correcting method — Revisited. Coastal Engineering, 93, Pages 15–31.

PhD thesis based on this code (Users)

Mayumi Wilms, 2018, Criteria of wave breaking onset and its variability in irregular wave trains (Englisch), Leibniz University of Hannover, Germany. https://www.tib.eu/de/suchen/id/TIBKAT%3A1028608276/Criteria-of-wave-breaking-onset-and-its-variability/

Users of this code outside IITM

  1. Leibniz University of Hannover, Germany 
  2. Grosser Wellen Kanal, GWK, Hannover.

Comments and Critics about this code:

When I started working on my research question for my dissertation in 2015, it turned out that I could not work on my topic exclusively with the traditional methods of physical laboratory experiments. I needed the support of numerical model experiments. Fortunately Sriram provided me with his numerical wave flume (FEM FNPT2D). Without this provision I would not have been able to complete my dissertation. Using the code was very easy and Sriram helped with any of my questions. In total I used about 6000 test runs for my analysis. Carrying out such a large number of test runs in the laboratory would not have been possible. The validation of the code using sample physical test runs turned out very well. Thanks to the code I was able to gain new valuable insights in the area of the beginning of wave breaking in irregular wave trains.
Thank you, Sriram!
Best wishes,
Bundesamt für Seeschifffahrt und Hydrographie, Hamburg, Germany.


The executable provided here is compiled using Intel Fortran and can only be used on Linux based OS such as Ubuntu and Mac. The code is proven to compile on Windows OS too, however that executable is not yet provided in the release and can be provided. The details are in the readme file.