Coupled physical-numerical analysis of flows in natural waterways
Journal of Hydraulic Research
The recent digital-electronic revolution has helped experimental hydraulics benefit from a new generation of acoustic-, laser-, and imaging-based instrumentation. These newly developed techniques are not only of superior accuracy, but they have also expedited data collection. Powerful visualization software has been used increasingly to present and interpret experimental results. In addition, numerical models have become increasingly available in some cases providing turnkey solutions to complex flows. The outcome of this intensive development is powerful computer-based research tools that allow an unprecedented interaction between physical and numerical experiments. This integrated approach is considerably improving our understanding of numerous aspects and practical consequences of flow mechanics and allows a comprehensive treatment of space-time processes in fluid flows which is difficult to obtain using alternative means. This holistic experimental-numerical approach is readily available for integration as expertsystems or decision-making programs in hydroinformatics systems. The present paper discusses the beneficial synergy between laboratory measurements and computational models of different levels of complexity. A study, conducted at the Iowa Institute of Hydraulic Research (IIHR) is presented herein as an example to demonstrate the interaction among the three investigation components, namely, laboratory measurements, the kinematic model, and the hydrodynamic model, as well as the benefits and limitations of each of them. The laboratory velocity measurements were made using three-component Acoustic-Doppler Velocimeters. A simple numerical model based exclusively on flow kinematics was used to empower results visualization and to provide insight in several flow features. The kinematic model feedback was used to optimize the data acquisition scheme for the ensuing measurements. The detailed hydrodynamic flow analysis for regions with complex three-dimensional flows was obtained by a numerical model that solves the Reynolds Averaged Navier-Stokes (RANS) equations in general curvilinear coordinates.
Published Article/Book Citation
Journal of Hydraulic Research, 39:1 (2001) pp.51-60.