206 Wind Tunnel Experiments of a Buoyancy Jet in a Cross Wind(Flow Characteristics in a Large-Scale Turbulence)

AbstractIn wind transport of snow, horizontal momentum is extracted from the mean wind flow and transferred to the snow grains. Upon colliding with the surface the grains can bounce and eject further grains in a process known as splashing. How efficiently the horizontal momentum is converted to vertical momentum in the splash process is the determining factor for mass-transport rates. This paper discusses wind-tunnel experiments performed to calculate the splash function for snow particles. The data are used to develop a new splash function. Particular care is taken to include correlations in the data such as between ejection velocity and ejection angle. The new splash function includes these correlations, and its parameters are related to physical properties of the bed and snow.

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Drag kings: characterizing large-scale flows in cycling aerodynamics

Journal of Fluid Mechanics ◽

10.1017/jfm.2014.146 ◽

2014 ◽

Vol 748 ◽

pp. 1-4 ◽

Cited By ~ 3

Author(s):

A. E. Hosoi

Keyword(s):

Wind Tunnel ◽

Large Scale ◽

Primary Source ◽

Vortex Wake ◽

Wind Tunnel Experiments ◽

Vortical Structures ◽

Drag Kings ◽

Full Rotation

AbstractIn their recent publication Crouch et al. (J. Fluid Mech., this issue, vol. 748, 2014, pp. 5–35) use wind tunnel experiments to quantify the large-scale vortical structures that develop as a cyclist progresses through a full rotation of the pedals. The authors identify asymmetries in the trailing vortex wake, which intensify as one leg straightens, as the primary source of drag variation over one pedal cycle. These new data suggest that targeted approaches to mitigate asymmetries in the trailing wake present an intriguing opportunity to reduce drag in cycling strategies and technologies.

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MEASUREMENT OF FLUID-STRUCTURE INTERACTION OF WIND TURBINES IN WIND TUNNEL EXPERIMENTS: CONCEPT AND FIRST RESULTS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w18-143-2019 ◽

2019 ◽

Vol XLII-2/W18 ◽

pp. 143-149

Author(s):

S. Nietiedt ◽

M. Goering ◽

T. Willemsen ◽

T. T. B. Wester ◽

L. Kröger ◽

...

Keyword(s):

Wind Tunnel ◽

Rotor Blade ◽

Spatial Information ◽

Measurement Techniques ◽

Rotor Blades ◽

Wind Flow ◽

Wind Tunnel Experiments ◽

Fluid Structure ◽

Measurement Concept ◽

Wind Flows

Abstract. Fluid-structure interactions are crucial for the design of rotor blades of wind power systems. Up to now, the mutual interactions between rotor blades and turbulent wind flows have been treated by complex simulations or were observed at individual discrete points. In this paper, a measurement concept is presented where spatial information of the motion/deformation of a rotating wind turbine as well as the wind flow are recorded in wind tunnel experiments. Wind flow and motion behaviour are recorded simultaneously and contactless. Techniques from the field of photogrammetry and flow measurement techniques are combined, resulting in high demands on the measurement concept. Furthermore, solutions for the realisation of a common coordinate system as well as for the synchronisation of both measuring systems are presented. In addition, the validation of the entire measurement concept is carried out based on of some wind tunnel tests in which a single rotor blade is used for the moment. This showed that the measurement concept and the proposed solutions for the simultaneous recording of wind flows and rotor blade movements are suitable in principle and that movements can be recorded and reconstructed with high accuracy.

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