Nays2D (Previous version of Nays2DH)

What is Nays2D ?

Nays2D is an analytical solver for calculation of unsteady two-dimensional plane flow and riverbed deformation using boundary-fitted coordinates within general curvilinear coordinates.

The solver's prototype was initially developed by Professor Yasuyuki Shimizu of Hokkaido University in the 1990s. After many improvements, it was first adopted in 2004 as a calculation solver for incorporation in the RIC-Nays*2 riverbed deformation calculation pre-post software of the Foundation of Hokkaido River Disaster Prevention Research Center (Version 1.0). Later refined by the inclusion of dynamic memory allocation*3 by Ichiro Kimura of Hokkaido University and outfitted with a bank erosion model by Yasuyuki Shimizu and a HotStart function by Toshiki Iwasaki of Hokkaido University, Nays2D (Version 2.0) was distributed as one of the solvers included with iRIC in 2010 at the release of iRIC Version 1.0. Further functional additions included the incorporation of a mixed-diameter multilayer model proposed by Toshiki Iwasaki, and a river confluence model proposed by Takuya Inoue and Michihiro Hamaki of Kaihatsu Koei Co., Ltd.
Nays2D was registered as a calculation solver for iRIC Version 2.0 in March 2011 under the planning and supervision of Kazutake Asahi from the Foundation of Hokkaido River Disaster Prevention Research Center (Version 3.0). 

This model has an established reputation for calculation of unsteady flows accompanied with turbulence and laminar flow, and it is capable of dynamically showing the realistic motions of unsteady eddies. In addition, its riverbed deformation calculations can reproduce the generation, development and migration of sandbars with high precision. There have been many examples of Nays2D being used on actual rivers for purposes such as assessing the effects of trees and vegetation, making flood calculations, studying the effects of inflowing rivers and simulating bank erosion disasters.


Nays2D solver (32bit)

Nays2D solver (32bit)

Nays2D solver (64bit)

Nays2D solver (64bit)

Solver Manual

Nays2D solver manual.

Examples

Nays2D Examples.

Sample data

Nays2D sample data.

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