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Quantitative Visualisation of Compressible Flows

Abstract

The paper demonstrates the feasibility of quantitative flow visualisation methods for investigation of transonic and supersonic flows. Two methods and their application for retrieving compressible flow field properties has been described: Background Oriented Schlieren (BOS) and Particle Image Velocimetry (PIV). Recently introduced BOS technique extends the capabilities of classical Schlieren technique by use of digital image processing and allow to measure density gradients field. In the presented paper a review of applications of BOS technique has been presented. The PIV is well established technique for whole field velocity measurements. This paper presents application of PIV for determination of the shock wave position above airfoil in transonic flow regime. The study showed that application of quantitative flow visualisation techniques allows to gain new insights on the complex phenomenon of supersonic and transonic flow over airfoils like shock-boundary layer interaction and shock induced flow separation.

Open access
Thermodynamic Model of the ASZ-62IR Radial Aircraft Engine

Abstract

The article presents assumptions of the one-dimensional model of the ASz-62IR aircraft engine. This model was developed in the AVL BOOST software. The ASz-62IR is a nine cylinder, aircraft engine in a radial configuration. It is produced by the Polish company WSK “PZL-Kalisz” S. A. The model is used for calculating parameters of the fuel stream and the air stream in intake system of the engine, as well as for the analyses of the combustion process and the exhaust flow to the external environment. The model is based on the equations describing the isentropic flow. The geometry of the channels and all parts of the model has been mapped on the basis of empirical measurements of the engine elements. The model assumes indirect injection where the gasoline was used as a fuel with the calorific value of 43.5 MJ/kg. The model assumes a mixture of a stoichiometric ratio of 14.5. This model is only part of the overall the ASz-62IR engine model. After the simulation tests on the full model the obtained results confirmed the correctness of the model used to create the mixture. It was found that the AVL BOOST software is good for the implementation of this type of work.

Open access
Various Types of The Rotorcraft Design in the Context of Aerospace Regulations

Abstract

In the next article on synthesis of regulations, the authors presented the general legal requirements for rotorcraft, which is limited to US regulations, because the vast majority of world regulations are based on them. The Institute of Aviation in Warsaw has developed requirements concerning the construction and operation of rotorcraft in Poland. These requirements constitute an important contribution to the regulations of the Civil Aviation Authority which are in force in the air space of the Republic of Poland. This paper presents the legal situation of rotorcraft and compares the requirements for helicopters and gyroplane. The conclusions highlighted the differences that arise from regulations between helicopters and rotorcraft. The authors have suggested the necessity to separate provisions for the group of windmills, which is implemented in the regulations of the Civil Aviation Authority. The presented work is the second of a planned series of publications in which authors intend to bring some of the issues to the reader about the design aspects of aircraft in selected global aviation regulations.

Open access
Aero-Structural Optimization of Joined-Wing Aircraft

Abstract

Joined-wing aircraft due to its energy characteristics is a suitable configuration for electric aircraft when designed properly. However, because of the specific for this aircraft phenomenons (e.g. static indeterminacy of structure, aerodynamic interference of lifting surfaces) it demands more complicated methods to model its behavior than a traditional aircraft configurations. For these reasons the aero-structural optimization process is proposed for joined-wing aircrafts that is suitable for preliminary design. The process is a global search, modular algorithm based on automatic geometry generator, FEM solver and aerodynamic panel method. The range of aircraft was assumed as an objective function. The algorithm was successfully tested on UAV aircraft. The improvement of 19% of total aircraft range is achieved in comparison to baseline aircraft. Time of evaluation of this global search algorithm is similar to the time characteristic for local optimization methods. It allows to reduce the time and costs of preliminary design of joined-wing.

Open access
Analysis of Delays and Extension of Execution Duration of a Road Project

Abstract

The implementation of road infrastructure projects often results in delays due to objective causes, with repercussions on the final execution deadline and with value implications. The use of critical path method for planning and the executin windows, will result in better time process management and optimization delays.

Open access
Designing and Building Heavy Lifting Modification of a Radio Controlled Helicopter

Abstract

The paper presents the heavy lifting modification of radio controlled T-Rex 700 DFC PRO helicopter which was originally designed as acrobatic machine. The purpose of designing machine like this is a need for a cheap and reliable machine specifically designed to carry weights for research and development purposes. Thanks to its design there is a possibility to attach to it a measuring apparatus, modules like auto-pilot, and weights. It can be also used to test wide range of rotors and other components which makes it very universal research tool. To achieve those goals the whole frame and landing gear has been redesigned using NX 11 CAD/CAM/CAE to achieve desired cargo space and weight distribution. Additionally the tail has been lengthened to allow use of the rotors with bigger diagonal. All the applied changes has been made to increase the machine payload. The designed elements were fabricated and the helicopter has been tested in flight. During the test flights several performance parameters were measured.

Open access
Improvement and Optimisation of Gyroplane Performance

Abstract

The aim of this study was to investigate possibilities of improving performance characteristics of light gyroplane, as well to propose new or improved solutions enhancing performance of this type of rotorcraft. The study has been conducted based on computational methods of Computational Fluid Dynamics, Flight Dynamics, Computer Aided Design and Optimisation. Results of the research confirm that using advanced computational methods it is possible to improve significantly the performance characteristics of light gyroplane. It can be achieved both through optimisation of the main rotor design and flight control strategy. An unconventional approach to rotorcraft optimisation has been presented, distinguishing by the fact that the objective was calculated based on computer simulations of selected states of gyroplane flight. One of the optimised main rotors had already been examined during flight tests, which confirmed its good perfonnance-and-exploitation properties and its advantage over classic gyroplane rotors. Developed by the author the family of gyroplane airfoils is a valuable alternative to classic airfoils utilised so far. The same applies to the blades built based on those airfoils. In particular, it concerns the unconventional design of the rotor blade of span-variable: chord and relative thickness. The developed methodology of numerical optimisation of flight-control strategy during the jump takeoff of the gyroplane presents an original approach to those problems and may be valuable tool supporting gyroplane-pilot training.

Open access
Influence of high temperatures on technical state of streets and roads structures with asphalt surfacing

Abstract

In this paper will be presented the influence of high temperatures on asphalt street pavement in terms of the influence of temperature on permanent deformations and thus the technical condition of the streets, comparable to the effects induced on extra-urban roads.

Environmental factors are one of the mayn factors being assaulted in operation and road structures are very important in terms of the influence they can have on the state road transport technical infrastructure.

Will be presented differences between urban road structures (streets) and extra-urban (road) both in terms of construction, the demands of traffic and environmental conditions to which they are subject.

Road structures extra-urban and urban areas are required differently in terms of the environmental conditions of the location ambient different thereof, that is, when the streets they are inside localities and the built environment significantly affect road infrastructure, unlike in the case of roads where they are located just outside the settlements, reducing the effect of air currents accumulation pavement surface temperature.

To demonstrate the influence of high temperatures on the pavement were conducted laboratory tests on asphalt mixtures in order to demonstrate the occurrence of reduction of physical characteristics, with adverse implications on the performance of applications similar to traffic.

Open access
Latin American Space Research - Challenges and Opportunities

Abstract

The interest of Latin American countries in space research has been successfully developing for many decades. It has its roots in the first development programmes for the Brazilian and Argentinian defence industry within the import substitution strategy, and then the export-oriented strategy during the period of the military rule. The endogenous development of space technology was treated in those countries as a priority and served as a way to diffuse technology to other industries, and as a model for the other countries in the region (Peru and Venezuela), which wished to develop outer space programme by developing their own technologies within the chosen range or by partaking in broader cooperation programmes on the Latin American continent [1]. The Latin American space agencies, which already existed in many countries in the 1960s and the 1970s, were carrying out relatively costly research, treating development in this area not only as the achievement of the economic development objectives, but also as an attempt to oppose the dominance of Washington [2]. Despite of the vast funding on endogenous research in the field of space engineering being provided, until the end of the last century only the projects conducted together with the Soviet Union (Cuba) or The United States were accomplished successfully. Currently and in the nearest future, the Latin American countries are still forced to rely on external assistance with satellite launching, expertise, more advanced technologies, etc. It should be noticed that countries conducting advanced and costly space programmes: the United States, Russia, China and the European Union (especially France and – but to a substantially lesser degree – Italy) show a growing interest in cooperation with Latin America and appreciation towards their specialists, high quality research and space technologies.

Open access
Mathematical Models for Nonlinear Soil Behavior

Abstract

Actually, the seismic movement has an irregular cyclic character.This can be equivalent to a determined number of uniform cyclical stresses equivalent in terms of effect.

Modeling the behavior of the soil to cyclical stress, is usually done, by establishing a relationship for primary loading like τ = f (γ) and after drawing the diagram “effortless strain curve”, in which τ is the stress, and γ is shear deformation. For modeling nonlinear behavior of the soil, we used like nonlinear models. The best known are the hyperbolic model and the Ramberg-Osgood model.

Open access