Determination of Flood Flow Depth and Velocity at the Threshold of Crop Rapture and Position of Rupture Point Using Analytical and Laboratory Analysis (Case Study: Rice)

Ganji Noroozi, Z.; Shokoohi, A.R.; Mohammad Vali Samani, J.

doi:10.30482/jhyd.2011.85504

Determination of Flood Flow Depth and Velocity at the Threshold of Crop Rapture and Position of Rupture Point Using Analytical and Laboratory Analysis (Case Study: Rice)

Document Type : Research Article

Authors

Z. Ganji Noroozi

A.R. Shokoohi

J. Mohammad Vali Samani

10.30482/jhyd.2011.85504

Abstract

Investigation on the behavior of plants, when exposed to hydrodynamic forces, is of vital importance
in flood analysis and evaluation of its consequent losses, design of channels and water resources
management. Because of the important effects of flow depth and velocity on plants' bending and
rapture point, the evaluation of which is necessary for flood loss estimation and its management across
the watershed. Studying the bending of plants and their probable rapture is not easy on account of
complicated interaction between plant and flow characteristics. In this paper, an analytical method is
presented for plant rapture in an un-submerged condition and static state and the outcomes are
compared with laboratory results. In this study, the multiplication of depth by flow velocity is used as
an index for the analysis of the plant rapture. The differences between the results of the analytical
solution and laboratory tests for the rapture index and the maximum tensile stress were less than 0.5
and 0.1 percents respectively. The results of the analytical solution and laboratory tests reveals that
under the same hydraulic conditions the rapture point for rigid plants with fixed diameter is located in
the plant's base, but this point will move upward for plants of variable diameter. In this regard, if the
reduction of the plant's diameter is relatively high, this point will be closer to the water surface.