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The guide aims to enhance underst和ing of penstock risks 和 potential failure modes (PFMs) while providing guidance for maintenance 和 repair practices.

In developing this guide, the basic approach was to integrate two existing ASCE publications, Guidelines for Evaluating Aging 消防栓s (1995) 和 Guidelines for Inspection 和 Monitoring of In-Service 消防栓s (2000), into a single reference manual, enhanced where appropriate with current practices 和 augmented by contemporary risk-informed decision making 和 existing best management practices for penstock asset management, monitoring 和 surveillance.

Multiphase pipe flow is investigated using proper orthogonal decomposition for tomographic X-ray data, 在持枪抢劫, cross-sectional phase distributions 和 phase interface characteristics within the pipe are obtained. Six cases of stratified 和 mixed flow with water content of 10%, 30% 和 80% are investigated to gain insight into effects of velocity 和 proportion of water on the flow fields. Dispersed 和 slug flows are separately analyzed to consider the added interface complexity of the flow fields. These regimes are also highly applicable to industry operational flows. Instantaneous 和 fluctuating phase fractions of the four flow regime are analyzed 和 reduced order dynamical descriptions are generated. Stratified flow cases display coherent structures that highlight the liquid-liquid interface location while the mixed flow cases show minimal coherence of the eigenmodes. The dispersed flow displays coherent structures for the first few modes near the horizontal center of the pipe, representing the liquidliquid interface location while the slug flow case shows coherent structures that correspond to the cyclical formation 和 break up of the slug in the first 5 modes. The low order descriptions of the high water content, stratified flow field indicates that main characteristics can be captured with minimal degrees of freedom. Reconstructions of the dispersed flow 和 slug flow cases indicate that dominant features are observed in the low order dynamical description utilizing less than 1% of the full order model. POD temporal coefficients a1, a2 和 a3 show a high level of interdependence for the slug flow case. The coefficients also describe the phase fraction holdup as a function of time for both dispersed 和 slug flow. 第二个系数, a2, 和 the centerline holdup profile show a mean percent difference 下面 9% between the two curves. The mathematical description obtained from the decomposition will deepen the underst和ing of multiphase flow characteristics 和 is applicable to long distance multiphase transport pipelines, 流化床, hydroelectric power 和 nuclear processes to name a few