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Full-Text Articles in Engineering
Secondary Motions Above A Staggered Multi-Scale Rough Wall, Bianca Viggiano, Juliaan Bossuyt, N. Ali, Johan Meyers, Raul Bayoan Cal
Secondary Motions Above A Staggered Multi-Scale Rough Wall, Bianca Viggiano, Juliaan Bossuyt, N. Ali, Johan Meyers, Raul Bayoan Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
Wind tunnel experiments were performed to investigate turbulent flow over an array of heterogeneous roughness elements using stereoscopic particle image velocimetry. Nine streamwise planes, covering one periodic cell of a multi-scale roughness element that is arranged in a staggered pattern, are combined to quantify mean flow features and Reynolds stresses. Dispersive stresses, arising from spatial variations in the temporally averaged mean velocity, are also presented. The results highlight that the roughness elements create a large deficit pathway along the surfaces. Outer scaling of the time-averaged streamwise velocity presents features which are nearly independent of the roughness element type, with parameters …
Characterization Of Coupling Between Inertial Particles And Turbulent Wakes From Porous Disk Generators, Kristin N. Travis, Sarah E. Smith, Laure Vignal, Henda Djeridi, Mickael Bourgoin, Raul Bayoan Cal, Martin Obligado
Characterization Of Coupling Between Inertial Particles And Turbulent Wakes From Porous Disk Generators, Kristin N. Travis, Sarah E. Smith, Laure Vignal, Henda Djeridi, Mickael Bourgoin, Raul Bayoan Cal, Martin Obligado
Mechanical and Materials Engineering Faculty Publications and Presentations
This study presents the findings of a wind tunnel experiment investigating the behaviour of micrometric inertial particles with Stokes numbers around unity in the turbulent wake of a stationary porous disk. Various concentrations Φv ∈ ([6 − 19] × 10−6) of poly-disperse water droplets (average diameter 40–50μm) are compared with sub-inertial tracer particles. Hot-wire anemometry, phase Doppler interferometry and particle image velocimetry were implemented in the near- and far-wake regions to study the complex dynamics of such particles. Quadrant analysis is used to explore the shear effects of the particle wake interaction. Turbulence statistics and particle size distributions reveal distinct …
Structure Functions, Scaling Exponents And Intermittency In The Wake Of A Wind Turbine Array, Naseem Ali, Aleksandr Sergeyevich Aseyev, Raúl Bayoán Cal
Structure Functions, Scaling Exponents And Intermittency In The Wake Of A Wind Turbine Array, Naseem Ali, Aleksandr Sergeyevich Aseyev, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
Hot-wire measurements obtained in a 3 × 3 wind turbine array boundary layer are utilized to analyze high order structure functions, intermittency effects as well as the probability density functions of velocity increments at different scales within the energy cascade. The intermittency exponent is found to be greater in the far-wake region in comparison with the near-wake. At hub height, the intermittency exponent is found to be null. Extended self-similarity scaling exponents of the second, fourth, and fifth order structure functions remain relatively constant as a function of height in the far-wake; whereas in the near-wake, these are highly affected …