Supercritical flow in bend with variable curvature radius

ABSTRACT

In this study, a new variable curvature bend called the maximum probability bend was applied to supercritical flows. Based on the maximum probability bend, the geometric and mechanical continuity of supercritical flow were studied, and the regulation of its superelevation, that is, the water surface elevation difference between both sides in every cross section, was analysed. The hydraulic characteristics of both the maximum probability bend and the traditional fixed curvature bend were experimentally investigated. It was found that the flow transitioned stably between straight and curve reaches in the maximum probability bend. Furthermore, the superelevation is reduced by a maximum of 65% compared with that in the traditional fixed curvature bend. Data comparison indicated that the proposed theory agreed well with the experimental results in terms of superelevation and the bend apex position. It was concluded that the maximum probability bend performed much better than the traditional fixed curve bend in supercritical flow control.

Keywords:

• Fixed curvature bend
• maximum probability bend
• supercritical flow
• superelevation
• surface profile

Additional information

Funding

The authors acknowledge the financial support by the National Key Research and Development Program of China [grant numbers 2016YFC0401603, 2016YFE0122500].