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Adatrao, S. (author), Sciacchitano, A. (author)
A novel approach is introduced that allows the elimination of undesired laser light reflections from particle image velocimetry (PIV) images. The approach relies upon anisotropic diffusion of the light intensity, which is used to generate a background image to be subtracted from the original image. The intensity is diffused only along the...
journal article 2019
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Del Estal Herrero, A. (author), Perçin, M. (author), Karasek, M. (author), van Oudheusden, B.W. (author)
Flow visualizations have been performed on a free flying, flapping-wing micro air vehicle (MAV), using a large-scale particle image velocimetry (PIV) approach. The PIV method involves the use of helium-filled soap bubbles (HFSB) as tracer particles. HFSB scatter light with much higher intensity than regular seeding particles, comparable to that...
journal article 2018
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Valori, V. (author)
Fluids above the critical point are widely used in industry. Chemical, pharmaceutical, food industry and energy production are some examples. In the energy production sector they are mainly used as cooling fluids, because they allow to increase the thermal efficiency of the power plants. However, the fundamentals of their heat transfer behavior...
doctoral thesis 2018
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Kislaya, A. (author), Sciacchitano, A. (author)
The use of optical diffusers for the reduction of peak-locking errors in particle image velocimetry is investigated. The working principle of the optical diffusers is based on the concept of birefringence, where the incoming rays are subject to different deflections depending on the light direction and polarization. The performances of the...
journal article 2018
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Sciacchitano, A. (author), Wieneke, Bernhard (author)
This paper discusses the propagation of the instantaneous uncertainty of PIV measurements to statistical and instantaneous quantities of interest derived from the velocity field. The expression of the uncertainty of vorticity, velocity divergence, mean value and Reynolds stresses is derived. It is shown that the uncertainty of vorticity and...
journal article 2016
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Lignarolo, L.E.M. (author)
The wake flow of a horizontal axis wind turbine is characterised by lower wind speed and higher turbulence than the free-stream conditions. When clustered in large wind farms, wind turbines regularly operate inside the wake of one or more upstream machines. This is a major cause of energy production loss and a source of higher fatigue loads on...
doctoral thesis 2016
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Pröbsting, S. (author)
Noise generated aerodynamically by the airflow over a lifting surface is often of concern for applications as diverse as air and ground transportation, heating, ventilation, air-conditioning systems, and wind turbines. The thesis describes the application of advanced optical flow measurements techniques for the visualization and description of...
doctoral thesis 2015
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Percin, M. (author)
The growing need for mobile aerial platforms capable of performing reconnaissance tasks and gathering intelligence in hazardous and physically inaccessible areas has given rise to an increasing interest in the development of micro aerial vehicles (MAVs), in view of their potential capabilities of versatile and highly maneuverable flight....
doctoral thesis 2015
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Birvalski, M. (author)
The growing demand for energy in the future will necessitate the production of natural gas from fields which are located farther offshore, in deep water and in very cold environments. This will confront us with difficulties in ensuring continuous production of the fluids (natural gas, condensate and water) emerging from a natural gas well. Often...
doctoral thesis 2015
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Tokgöz, S. (author)
Taylor-Couette flow is defined as the flow confined between two coaxial cylinders which can rotate independently. Several different flow states can be observed in the gap between the cylinders by changing the rotation speeds and the rotating directions of the cylinders. The aim of this thesis is to investigate the previously reported change of...
doctoral thesis 2014
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Sciacchitano, A. (author)
Particle Image Velocimetry (PIV) is a well-established technique for the measurement of the flow velocity in a two or three-dimensional domain. As in any other technique, PIV data is affected by measurement errors, defined as the difference between the measured velocity and its actual value, which is unknown. Aim of uncertainty quantification is...
doctoral thesis 2014
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Koschatzky, V. (author)
This thesis deals with the problem of noise. Sound is a constant presence in our lives. Most of the times it is something wanted and it serves a purpose, such as communication through speech or entertainment by listening to music. On the other hand, quite often sound is an annoying and unwanted by-product of some other activity necessary to us....
doctoral thesis 2011
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Van Oudheusden, B.W. (author), Jöbsis, A.J.P. (author), Scarano, F. (author), Souverein, L.J. (author)
The spatio-temporal dynamics of an impinging shock/boundary layer interaction atMach 2 and under incipient separation conditions, has been investigated experimentally by means of high-speed particle image velocimetry (PIV). The available PIV acquisition rate of up to 20 kHz permits a time-resolved characterization of the interaction. The...
journal article 2011
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Schrijer, F.F.J. (author)
To further improve the design of hypersonic vehicles so that fully reusable systems become a reality, the detailed understanding of the ?ow ?eld that the vehicle generates is of paramount importance. The thesis deals with the aspects of experimental ?ow research which includes also the ?ow facility and the measurement techniques. First a...
doctoral thesis 2010
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Humble, R.A. (author)
A fundamental experimental study is carried out to investigate the unsteady flow organization of an incident shock wave/turbulent boundary layer interaction at Mach 2.1. Planar and tomographic particle image velocimetry (PIV) are used in combination with data processing using the proper orthogonal decomposition (POD), complemented with hot-wire...
doctoral thesis 2009
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Ooms, T.A. (author)
This thesis contributes to the development of an instrument that can measure fluid flow velocity in a three-dimensional (3D) measurement domain by holographic imaging.
doctoral thesis 2008
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Vennemann, P. (author)
The development, the regulation, and the pathology of the circulatory system (e.g. cardiogenesis, thermoregulation, atherosclerosis) are determined by blood flow induced mechanical forces. While this proposition has been confirmed during recent years, the exact mechanisms still remain unclear. This is mainly due to the fact that those forces...
doctoral thesis 2008
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Schrijer, F.F.J. (author), Mignoli, G. (author), Scarano, F. (author), Walpot, L.M.G.F.M. (author)
conference paper 2008
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Lienhart, H. (author), Gomes, J.P. (author)
Experimental studies on reference test cases are of capital importance to support the development of models and coupling strategies for simulations on fluid-structure interaction problems. The need for experimental test cases specially addressed for the validation and diagnostic of numerical tools has triggered the present contribution to design...
conference paper 2006
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Elsinga, G.E. (author), Van Oudheusden, B.W. (author), Scarano, F. (author)
In PIV particle image blur is usually observed near fluid optical interfaces, i.e. shock waves, and thin flow structure with large density variations, e.g. shear layers and boundary layers. In such an environment the particle image is not only subject to blur, but is also displaced from its actual position due to refraction, which is denoted as...
conference paper 2005
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