Research group

Computational Fluid Dynamics

– in Hydraulic Engineering

Our department has been using and developing CFD models for hydraulic and sedimentation engineering since 1990. Initial work was focused on sediment problems with regards to hydropower intakes, primarily due to the difficulties of modelling fine sediment in physical models. Since then the scope of our CFD research has expanded to other hydraulic and environmental topics.

Grid - Self-forming meandering channel

The picture above shows the grid of a self-forming meandering channel. The colours show the bed levels. More information.

More information:

Computer Programs

Most of our CFD work has been carried out using the SSIIM program. The program is based on the solution of the Navier-Stokes equations on a non-orthogonal 2D or 3D grid. Both structured and unstructured grid versions are used. The SIMPLE method is used for computing the pressure and the the k-epsilon model is used to calculate turbulence. The sediment transport is calculated by solving the convection-diffusion equation for sediment concentration. Changes in bed elevation over time are computed, and algorithms for wetting and drying enables the prediction of lateral channel movements.

More information and download instructions for SSIIM


On-line books

We have made some CFD books publically available on the PDF format. A short description and download links are given below.

CFD class notes (593 kB)

"Computational Fluid Dynamics for Hydraulic and Sedimentation Engineering" was made for the CFD part in our class "Withdrawal of water from sediment-carrying rivers". The class notes provides a simple introduction to the basics of CFD. The latest version was made 16. June 1999.

User's manual for SSIIM (1.3 MB)

The user's manual for SSIIM provides standard information about the SSIIM program, like user interface, data format for input and result files etc. The latest version was made 31. May 2010.

Numerical modelling and hydraulics (1.7 MB)

The class notes for a course with the same name, given for the first time in the spring 2001. It is an undergraduate course in the 4th year of the Civil Engineering study at NTNU. This is the version from October 2009.

CFD Algorithms for Hydraulic Engineering (678 kB)

The book is a more detailed documentation of general and special hydraulic engineering CFD algorithms. It is intended to be used as a textbook for graduate courses in CFD, and also to provide assistance for people writing CFD codes. The present version is from 14. December 2000, and before this date it has not been checked by anyone but the author.

CFD for Hydraulic Structures (535 kB)

The book is about experiences using the SSIIM model to compute flow in/around hydraulic structures. The following cases are discussed: Vegetation, spillways, local scour and intakes. The present version is from 8. May 2001.


Several examples from our research are listed below. Much of the work has been carried out in cooperation with other institutions, so many of the examples are located on other web servers.

The numbers in brackets indicate size of graphics files in kB. The date indicate latest update.

Sediment transport

General hydraulics

Water quality

Habitat hydraulics

Habitat modelling in Gurobekken laboratory flume at SINTEF, Norway, 15. Nov. 2000
Sea trout spawning habitat in Gråelva, Norway, 31. Oct. 2001

Activities and seminars

There are no upcoming seminars at the moment.

Key contact:

Nils Reidar B. Olsen