Flow field diagnostics - Topological flow changes and spatio-temporal flow structure

AbstractIn continuous casting DC magnetic fields perpendicular to the wide faces of the mold are used to control the flow in the mold. Especially in this case, even a rough knowledge of the flow structure in the mold would be highly desirable. The contactless inductive flow tomography (CIFT) allows to reconstruct the dominating two-dimensional flow structure in a slab casting mold by applying one external magnetic field and by measuring the flow-induced magnetic fields outside the mold. For a physical model of a mold with a cross section of 140 mm×35 mm we present preliminary measurements of the flow field in the mold in the presence of a magnetic brake. In addition, we show first reconstructions of the flow field in a mold with the cross section of 400 mm×100 mm demonstrating the upward scalability of CIFT.

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Extension and Expression of OWL Modeling Primitives Based on Spatio-Temporal Ontology of Ocean Flow Field

Communications in Computer and Information Science - Geoinformatics in Sustainable Ecosystem and Society ◽

10.1007/978-981-15-6106-1_24 ◽

2020 ◽

pp. 321-335

Author(s):

Min Ji ◽

Qingsong Shi ◽

Fengxiang Jin ◽

Ting Li ◽

Yong Sun

Keyword(s):

Flow Field ◽

Temporal Ontology ◽

Spatio Temporal

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Near-Wake Flow Structure of a Suspended Cylindrical Canopy Patch

Water ◽

10.3390/w12010084 ◽

2019 ◽

Vol 12 (1) ◽

pp. 84 ◽

Cited By ~ 1

Author(s):

Ayşe Yüksel Ozan ◽

Didem Yılmazer

Keyword(s):

Flow Field ◽

Flow Structure ◽

Green Infrastructure ◽

Nutrient Management ◽

Wake Flow ◽

Wake Region ◽

Near Wake ◽

Vegetation Patch ◽

Comprehensive Picture ◽

Flowing Waters

Urban stormwater is an important environmental problem, especially for metropolitans worldwide. The most important issue behind this problem is the need to find green infrastructure solutions, which provide water treatment and retention. Floating treatment wetlands, which are porous patches that continue down from the free-surface with a gap between the patch and bed, are innovative instruments for nutrient management in lakes, ponds, and slow-flowing waters. Suspended cylindrical vegetation patches in open channels affect the flow dramatically, which causes a deviation from the logarithmic law. This study considered the velocity measurements along the flow depth, at the axis of the patch, and at the near-wake region of the canopy, for different submerged ratios with different patch porosities. The results of this experimental study provide a comprehensive picture of the effects of different submergence ratios and different porosities on the flow field at the near-wake region of the suspended vegetation patch. The flow field was described with velocity and turbulence distributions along the axis of the patch, both upstream and downstream of the vegetation patch. Mainly, it was found that suspended porous canopy patches with a certain range of densities (SVF20 and SVF36 corresponded to a high density of patches in this study) have considerable impacts on the flow structure, and to a lesser extent, individual patch elements also have a crucial role.

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Analysis of Measurements in Vaned Diffusers of Centrifugal Compressors

Journal of Turbomachinery ◽

10.1115/1.3262156 ◽

1988 ◽

Vol 110 (1) ◽

pp. 115-121 ◽

Cited By ~ 1

Author(s):

W. Stein ◽

M. Rautenberg

Keyword(s):

Flow Field ◽

Flow Structure ◽

Calculation Method ◽

Geometric Parameters ◽

Variable Geometry ◽

Centrifugal Compressors ◽

Wide Range ◽

Performance Curves ◽

Different Types ◽

Flow Phenomena

In vaned diffusers of centrifugal compressors many different flow phenomena interfere with one another, and different geometric parameters influence the flow field. Variations of these parameters allow the designer to optimize the diffuser for a certain application or to use a variable geometry for controlling the stage over a wide range. Two vaned diffusers that differ only in their passage widths are investigated using different types of measuring technique, in order to analyze the flow structure and to use it as a verification of a calculation method that allows detailed predictions of flow field parameters inside the diffuser, by taking into account geometric variations. Using this method predictions of the flow field of a variable geometry diffuser are made and are compared with the measured performance curves of the stage.

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Analysis of Local Flow Structure and Global Compressor Performance During Rotating Stall

Volume 5: Turbo Expo 2004, Parts A and B ◽

10.1115/gt2004-53816 ◽

2004 ◽

Author(s):

Chiara Palomba

Keyword(s):

Flow Field ◽

Flow Structure ◽

Rotational Speed ◽

Axial Flow ◽

Rotating Stall ◽

Performance Parameters ◽

Flow Conditions ◽

Local Flow ◽

Flow Parameters ◽

Compressor Performance

Rotating stall is an instability phenomenon that arises in axial flow compressors when the flow is reduced at constant rotational speed. It is characterised by the onset of rotating perturbations in the flow field accompanied by either an abrupt or gradual decrease of performances. Although the flow field is unsteady and non axisymmetric, the global operating point is stable and a stalled branch of performance curve may be experimentally determined. The number, rotational speed, circumferential extension of the rotating perturbed flow regions named rotating cells may vary from one compressor to another and may depend on the throttle position. The present work focuses on the interaction between local flow parameters and global compressor performance parameters with the aim of reaching a better understanding of the phenomenon. Starting from the Day, Greitzer and Cumpsty [1] model the detailed flow conditions during rotating stall are studied and related to the global performance parameters. This is done both to verify if the compressor under examination fits to the model and if the detailed flow structure may highlight the physics that in the simple model may hide behind the correlation’s used.

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