scholarly journals Experimental techniques in the wind tunnel of naval architecture faculty

2021 ◽  
Vol 44 ◽  
pp. 5-10
Author(s):  
Dan Obreja
Keyword(s):  
Fluid Flow ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Experimental Model ◽  
Numerical Solutions ◽  
Experimental Techniques ◽  
Aerodynamic Forces ◽  
Naval Architecture ◽  
Innovative Solutions ◽  
The University

The implementation of innovative solutions in the field of shipbuilding requires the continuous development of research infrastructure. The hydro-aerodynamic problems of fluid flow around the hulls can be solved with numerical and/or experimental techniques. In any case, the validation of the numerical solutions is performed in specialized hydro-aerodynamic laboratories by means of the experimental model tests. In this context, a wind tunnel was developed at the Naval Architecture Faculty of “Dunarea de Jos” University of Galati, in order to measure the aerodynamic forces and moments or the speed and pressure distribution on the hull, generated by the wind action. This paper presents the most important types of problems that can be experimentally approached in the aerodynamic tunnel and the specific experimental equipments. The wind tunnel development was financed from the university funds.

scholarly journals Estimation of Aerodynamic Load on Radome Structure Mounted on Top of a Surveillance Aircraft

2020 ◽  
Vol 9 (3) ◽  
pp. 1969-1973
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Structural Design ◽  
Pressure Transducer ◽  
Dorsal Side ◽  
Aerodynamic Load ◽  
Aerodynamic Forces ◽  
Support Structure ◽  
Aerodynamic Angles ◽  
Valve Pressure

The design and development of radome external structure, requires aerodynamic forces acting on it and its distribution. This paper discusses the wind tunnel studies carried out for estimating the incremental effects due to the installation of large ellipsoidal radome along with the support structure pylons on the dorsal side of the fuselage. Effect of locations of radome at 36 m and 31.5 m from the nose of the fuselage is discussed. Further using the scan-valve pressure transducer, the pressure distribution on the radome measured at different aerodynamic angles required for the structural design of radome structure is also brought out. Flow visualization study which are useful for qualitative check for the effect of installation of the radome with support structure on the effectiveness of the empennage is attempted.

scholarly journals Experimental model tests to improve a tanker resistance performance

2021 ◽  
Vol 44 ◽  
pp. 11-14
Author(s):  
Dan Obreja
Keyword(s):  
Experimental Model ◽  
Model Tests ◽  
Experimental Techniques ◽  
Naval Architecture ◽  
Towing Tank ◽  
Ship Resistance ◽  
Design Speed ◽  
Bulbous Bow ◽  
Resistance Performance ◽  
Ship Speed

The ship resistance is one of the most important hydrodynamics performances, being related to the contractual ship speed. The experimental model tests can be used to measure and improve the resistance performance. In this paper, the possibility of using the experimental techniques in order to improve a tanker model resistance is demonstrated, based on a bulbous bow modelling solution. In this context, the results obtained in the Towing Tank of the Naval Architecture Faculty of “Dunarea de Jos” University of Galati, related to a tanker model resistance with and without bulbous bow are presented. The bulbous bow form was realised based on the hydrodynamics principles adapted to the bow forms of the tanker. In the case of the bulbous bow solution, a significant reduction of over 8% of the tanker model resistance was obtained, in the design speed domain.

Extremely Gusty Winds from a Viewpoint of Aerodynamic Force

2020 ◽  
Author(s):  
Junji Maeda ◽  
Takashi Takeuchi ◽  
Eriko Tomokiyo ◽  
Yukio Tamura
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Rise Time ◽  
Aerodynamic Force ◽  
Step Function ◽  
Object Size ◽  
Aerodynamic Forces ◽  
Wind Force ◽  
Wind Observation

To quantitatively investigate a gusty wind from the viewpoint of aerodynamic forces, a wind tunnel that can control the rise time of a step-function-like gust was devised and utilized. When the non-dimensional rise time, which is calculated using the rise time of the gusty wind, the wind speed, and the size of an object, is less than a certain value, the wind force is greater than under the corresponding steady wind. Therefore, this wind force is called the “overshoot wind force” for objects the size of orbital vehicles in an actual wind observation. The finding of the overshoot wind force requires a condition of the wind speed recording specification and depends on the object size and the gusty wind speed.

DSSC-Integrated Glassblocks for the Construction of Sustainable Building Envelopes

2014 ◽  
Vol 875-877 ◽  
pp. 629-634 ◽  
Author(s):  
Rossella Corrao ◽  
Dario D'Anna ◽  
Marco Morini ◽  
Luisa Pastore
Keyword(s):  
Energy Efficient ◽  
Light Transmittance ◽  
Building Envelopes ◽  
Sustainable Building ◽  
Building Product ◽  
Building Integrated Photovoltaics ◽  
Pv Systems ◽  
Innovative Solutions ◽  
First Results ◽  
The University

The paper shows the first results of the optical performance analysis carried out on the DSSC integrated glassblock, an innovative building product developed at the Department of Architecture of the University of Palermo. In the field of a research that is being conducted in order to define innovative solutions for the construction of photovoltaic and energy efficient translucent building envelopes, different hypotheses of integration of DSSC into the glassblock have been foreseen. The integration of glassblock with third generation PV systems allows to define a novel building-PV product that meets the current requirements of the BIPV (Building Integrated Photovoltaics) market. By means of OptiCAD® software, several numerical simulations were conducted to analyse the solar factor, the light transmittance and the shading coefficient of the device.

W-band beam-steerable MEMS-based reflectarray

2011 ◽  
Vol 3 (5) ◽  
pp. 521-532 ◽  
Author(s):  
Simone Montori ◽  
Elisa Chiuppesi ◽  
Paola Farinelli ◽  
Luca Marcaccioli ◽  
Roberto Vincenti Gatti ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Imaging System ◽  
Elementary Cell ◽  
Control Architecture ◽  
Micro Electro Mechanical Systems ◽  
Concealed Weapons ◽  
W Band ◽  
Innovative Solutions ◽  
Wave Imaging ◽  
The University

This paper presents recent advances on reconfigurable reflectarrays at the University of Perugia. In particular, the activities carried out in the framework of the FP7 project ARASCOM (“MEMS and Liquid Crystal based” Agile Reflectarray Antennas for Security and COMmunication). As for ARASCOM outcomes, the purpose of the project is the design of a very large reconfigurable reflectarray controlled with micro-electro-mechanical systems (MEMS) for mm-wave imaging system at 76.5 GHz. A system with sufficient resolution to detect concealed weapons impose challenging requirements on the antenna, which shall be made of hundreds of thousands elements. The problem has been addressed by exploiting some innovative solutions and architectures that will be described in this document. In particular, the dimensioning of the reflectarray, the proposed 1-bit geometry of elementary cell, and the innovative biasing control architecture are reported together with the MEMS design and fabrication and the experimental results of a demonstrating board that validated the adopted procedure.

Investigations on Aerodynamic Loading Limits of Subsonic Compressor Tandem Cascades: Midspan Flow

2013 ◽  
Author(s):  
Charlotte Hertel ◽  
Christoph Bode ◽  
Dragan Kožulović ◽  
Tim Schneider
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Numerical Simulations ◽  
Pressure Distribution ◽  
Large Range ◽  
Pressure Rise ◽  
Transition Model ◽  
Diffusion Factor ◽  
Aerodynamic Loading ◽  
Tandem Cascades

An optimized subsonic compressor tandem cascade was investigated experimentally and numerically. Since the design aims at incompressible applications, a low inlet Mach number of 0.175 was used. The experiments were carried out at the low speed cascade wind tunnel at the Technische Universität Braunschweig. For the numerical simulations, the CFD-solver TRACE of DLR Cologne was used, together with a curvature corrected k-ω turbulence model and the γ-Reθ transition model. Besides the incidence variation, the aerodynamic loading has also been varied by contracting endwalls. Results are presented and discussed for different inlet angles and endwall contractions: pressure distribution, loss coefficient, turning, pressure rise, AVDR and Mach number. The comparison of experimental and numerical results is always adequate for a large range of incidence. In addition, a comparison is made to an existing high subsonic tandem cascade and conventional cascades. For the latter the Lieblein diffusion factor has been employed as a measure of aerodynamic loading to complete the Lieblein Chart of McGlumphy [1].

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