Dropshaft Hydrodynamics under Transient Conditions
Publication: Journal of Hydraulic Engineering
Volume 117, Issue 8
Abstract
The hydrodynamics of a dropshaft‐drift tube system under two transient conditions, namely, rapid increase of dropshaft inflow and strong main tunnel surge, is studied analytically and numerically. The governing equations are derived, and then linearized to explicitly represent the system's responses to external disturbances. The linearized study shows that the water column in the dropshaft oscillates sinusoidally in response to a disturbance. The amplitude of the oscillation was found to increase with the strength of disturbance as well as the fundamental period of the system. For inflow‐caused disturbances, a typical dynamic instability phenomenon exhibited by growing amplitude of oscillations may exist under certain conditions. For both types of disturbances, the amplitude can be so large that water in the dropshaft may overshoot the ground surface, causing damages. The analytical results are verified by direct numerical solutions of the original nonlinear equations and field records.
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Information & Authors
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Published In
Journal of Hydraulic Engineering
Volume 117 • Issue 8 • August 1991
Pages: 1042 - 1055
Copyright
Copyright © 1991 ASCE.
History
Published online: Aug 1, 1991
Published in print: Aug 1991
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