Study of disturbance wave development in downwards annular flows with a moving frame‐of‐reference brightness‐based laser‐induced fluorescence method
| Autor: | Christos N. Markides, Andrey V. Cherdantsev, Jae Sik An, Ivan Zadrazil |
|---|---|
| Přispěvatelé: | Engineering & Physical Science Research Council (EPSRC), The Royal Society |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Brightness geography Disturbance (geology) geography.geographical_feature_category System of measurement Fluids & Plasmas Flow (psychology) Computational Mechanics General Physics and Astronomy Reynolds number Mechanics Inlet 0915 Interdisciplinary Engineering 0901 Aerospace Engineering Physics::Fluid Dynamics symbols.namesake Flow conditions Mechanics of Materials Moving frame symbols 0913 Mechanical Engineering |
| Popis: | Abstract A novel moving frame-of-reference brightness-based laser-induced fluorescence (MFoR-BBLIF) method was developed and demonstrated in downwards co-current air–water annular flows. The method was applied to study the downstream development of individual disturbance waves in flows over a range of conditions (ReL = 276–1321, ReG = 39,500–79,000). In this method, the optical measurement system, and hence, the region of interrogation (ROI) was translated physically along the length of the test-section with a velocity close to that of individual disturbance waves to obtain the velocities of individual disturbance-waves as a function of downstream distance from the inlet. It was found that the velocities of individual disturbance waves increase with both downstream distance and gas–liquid flow conditions. In addition, the variation in the wave velocities was more significant at higher gas and liquid Reynolds numbers. The approach can be integrated with many other contactless measurement methods, and can also be used over a range of translation speeds (not necessarily in a “Lagrangian” manner) to study the evolution of important advecting flow phenomena. Graphic abstract |
| Databáze: | OpenAIRE |
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