On Cup Anemometer Rotor Aerodynamics

The influence of anemometer rotor shape parameters, such as the cups��� front area or their center rotation radius on the anemometer���s performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups��� center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor���s cup.

Static Pressure Impact on Aerodynamics of High Speed Railway Tunnels

A pressure wave is generated when a high speed train enters a tunnel. This wave travels along the tunnel back and forth, and is reflected at the irregularities of the tunnel duct (section changes, chimneys and tunnel ends). The pressure changes are associated to these waves can have an effect on passengers if the trains are not suitably sealed or pressurized. The intensity of the waves depends mainly on the train speed, and on the blockage ratio (train-section-to- tunnel-section area ratio). As the intensity of the waves is limited by regulations, and also by the effects on passengers and infrastructures, the sizing of the tunnel section area is largely influenced by the maximum train speed allowed in the tunnel. The aim of this study is to analyse the increase in cost in a tunnel due to the existence of this difference in ground level, and evaluate the increase of construction costs that this elevation might involve.

Some developments on cup anemometer aerodynamics

In the present study the geometry of cups is experimentally studied through anemometer performance. This performance is analyzed in two different ways. On the one hand the anemometer transfer function between cases is compared. On the other hand the stationary rotation speed is decomposed into constant and harmonic terms, the comparison being established between the last ones. Results indicate that some cup shapes can improve the uniformity of anemometer rotation, this fact being important to reduce degradation due to ageing.

Numerical and experimental study of appendages in racing yachts and their influence on the free surface

Las prestaciones de un velero de regatas se estiman por medio de los Programas de Predicci��n de Velocidad (VPP) que incluyen las caracter��sticas de estabilidad y modelos aero e hidrodin��mico del barco. Por esta raz��n, es importante tener una evaluaci��n adecuada de las fuerzas en ap��ndices y de su variaci��n en diferentes condiciones de navegaci��n, escora y deriva. Adem��s, para el c��lculo de las fuerzas en los ap��ndices es importante conocer sus caracter��sticas hidrodin��micas cuando trabajan conjuntamente en un campo fluido fuertemente modificado por la carena. Por esta raz��n, se han utilizado una serie de ensayos realizados en el Canal de Ensayos de la ETSIN con el objetivo de validar c��digos num��ricos que permiten una evaluaci��n m��s r��pida y focalizada en los distintos fen��menos que se producen. Dichos ensayos se han realizado de forma que pudiera medirse independientemente las fuerzas hidrodin��micas en cada ap��ndice, lo que permitir�� evaluar el reparto de fuerzas en diferentes condiciones de navegaci��n para poder profundizar en las interacciones entre carena, quilla y tim��n. Las t��cnicas num��ricas permiten capturar detalles que dif��cilmente se pueden visualizar en ensayos experimentales. En este sentido, se han probado las ��ltimas t��cnicas utilizadas en los ��ltimos workshops y se ha enfocado el estudio a un nuevo m��todo con el objetivo de mostrar una metodologia m��s r��pida que pueda servir a la industria para este tipo de aproximaci��n al problema. ABSTRACT The performances of a racing sailboat are estimated by means of the speed prediction programs (VPP), which include the ship stability characteristics and the aero and hydrodynamic models. For this reason, it is important to have an adequate evaluation of the forces in appendices and its variation in different sailing conditions, heel and leeway Moreover, for the analysis of the forces in the appendices, it is important to know their hydrodynamic characteristics when they work together in a fluid field strongly modified by the canoe body. For this reason, several tests have been done in the ETSIN towing tank with the aim to validate numeric codes that allowing faster analysis and they permit to focus on the different phenomena that occur there. Such tests have been done in a way that the hydrodynamic forces in each appendage could be measured independently allowing assessing the distribution of forces in different sailing conditions to be able to deepen the interactions between the canoe body, the keel and the rudder. Numerical techniques allow capturing details that can hardly be displayed in experimental tests. In this sense, the latest techniques used in the recent workshops have been reviewed and the study has been focused to propose a new model with the aim to show a new faster methodology which serves the industry for this type of approach to the problem.

Environmental change and hedonic cost functions for���automobiles

This paper focuses on how changes in the economic and regulatory environment have affected production costs and product characteristics in the automobile industry. We estimate ���hedonic cost functions��� that relate product-level costs to their characteristics. Then we examine how this cost surface has changed over time and how these changes relate to changes in gas prices and in emission standard regulations. We also briefly consider the related questions of how changes in automobile characteristics, and in the rate of patenting, are related to regulations and gas prices.

A computer program (VEHSIM) for vehicle fuel economy and performance simulation (automobiles and light trucks). Volume I: description and analysis. Final report.

National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.

A computer program (VEHSIM) for vehicle fuel economy and performance simulation (automobiles and light trucks). Volume II: users guide. Final report.

National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.

A computer program (VEHSIM) for vehicle fuel economy and performance simulation (automobiles and light trucks). Volume IV: enhancements. Final report.

National Highway Traffic Safety Administration, Office of Research and Development, Washington D.C.

Requests by General Motors and Ford to reduce fuel economy standards for MY 1981-85 passenger automobiles. Report.

Mode of access: Internet.

Elements of aerodynamics of supersonic flows.

Bibliography: p. 385-387.

Human factors aspects of using head up displays in automobiles: a review of the literature.

National Highway Traffic Safety Administration, Washington, D.C.