Purpose The purpose of this research is a preliminary selection of wing section, which would be the best suited for PW-100 – a MALE class UAV of 600 kg weight. PW-100 will be used as a testing platform in different institutions such as research institutes, industry research centers or universities of technology (phase 1) to enable the in-flight testing of various on-board systems (mobile radars, thermovision sensors, chemical sensors, antennas, teledetection systems and others). Untypical layout of PW-100 resulted from the plans of further development of this configuration for a military application. Design/methodology/approach Important role in the research described in this paper plays the selection of main wing section to fulfil the preliminary requirements regarding maximum lift coefficient, minimum drag, aerodynamic efficiency etc. Two different wing sections (R1082 and SA19) were tested in wind tunnel, both with flaps deflected at the range of 0°-30°. Experimental measurements were performed in the low turbulence wind tunnel with closed test section of 45 cm × 35 cm. Numerical simulations of the flow around the wing sections were performed using MSES code. Boundary conditions were assumed basing on the typical mission of PW-100 for flight altitude around 9,000 m, speed of 110 km/h what results in Re = 956,000. Findings Lift coefficients obtained from both experimental and numerical methods for single slatted airfoil SA19 are much higher than that of get for Ronch R1082 airfoil. PW-100 aircraft with SA19 airfoils will be able to be trimmed and fly at any altitude up to 9,000 m and with an arbitrary weight up to 600 kg. Aerodynamic characteristics of SA19 remain smoother and more predictable than that of R1082 airfoil. The very promising properties of SA19 airfoil are well known to the authors since the beginning of last decade when PW team worked together with IAI team on CAPECON project and now it was fully confirmed by this research. Practical implications It was confirmed that selection of the proper wing section for the special mission performed by UAV is of the highest importance decision to be taken at the preliminary design phase. Because there is a limited access to the base of technical parameters in many different UAVs classes and the classical analysis of trends cannot be fully applied, the wing section analysis, either experimental or numerical, must be performed. The situation is much worse than in the case of manned aircrafts because most of the modern UAVs are made of carbon or glass fiber, and therefore, there is no chance for analysis of trends. Originality/value This paper presents a very efficient method of assessing the influence of wing section on aircraft performance adopted for MALE class UAV, especially in an early stage of preliminary design process. The assessment is built mainly on three requirements: Maximum 2D lift coefficient for take-off configuration with flap deflected on 20 degrees should be greater than 2.4. Endurance factor CL1.5/CD for loitering conditions (Ma = 0.5 and CD0 = 0.008) should be greater than 110. The relative wing section thickness should be greater/equal than 19 per cent (it is required for high volume fuel tank located in the wings).

This paper discusses an application of air curtain for reduction of virus-laden droplets transmission from an infected host to other passengers in a small aircraft cabin. The study is restricted to respiratory droplets emitted during coughing. Discrete Particle Method introduced for violent respiratory events (VRE) captured in detail the movement of coughing puff inside the cabin and allowed to study the interaction of droplets with the air curtain’s stream and the surrounding air. The results show that the application of the air curtain inhibits the transmission process of small droplets (diameters ranging from 10 to 40 μm). The air curtain supplied with a limited air mass flow cannot alter the multiphase puff dynamics, but it can be utilized to deflect the virus droplets with lower momentum away from the neighboring passenger. Improved removal efficiency of virus-laden droplets has been achieved owing to the application of the air curtain together with supplementary suction surfaces introduced on the front seat backrest. The virus (SARS-CoV-2) transmission process was also analyzed by means of mass concentration of CO2 exhaled by the infected host, used as a contamination tracker. This part of the work aims at assessment of an applicability of CO2 tracer gas in analysis of virus transmission. Results show that CO2 tracer gas can only be employed for the study of small size droplets dispersion (diameter less or equal to 40 μm).

The chapter focuses on explaining the construction of author's own engineering-level model which calculates energy production based on historical water level and flow rate readings as well as economic factors such as net present value of the proposed investment on the example of a HPP on the Wkra River. The model methodology assumes the identification of location's hydrological features and translates them into a set of contingency scenarios. Various internal costs, such as maintenance or labor costs, related to normal HPP activity and taxation are discussed and incorporated into the economic part of the model. Test case results indicate that for a series of good years in terms of water flow and electricity production, full repayment of initial investment costs is possible after less than three years. Results for the chosen modernization parameters indicate that within 10 years of installing a new turbine, even the most pessimistic case would bring added value to the real estate valuation.

This paper presents the optimization of multi-element aerofoil for the LAR-3 Puffin -- STOL light transport aircraft concept proposal. Based on the geometry and aerodynamic characteristics of the well-known and proven in flight three-segment NACA 63A416 aerofoil, the authors explore the possibility of enhancing its high-lift performance by the movement of slot and flap position in extended (deployed) aerodynamic configuration. In order to determine the optimum positions of aerofoil segments (elements), a multi-step optimization approach was developed. It combines computational fluid dynamics simulations that were used for design space screening and preliminary optimization together with low-turbulence wind tunnel tests which yielded certain results. To decrease the numerical cost of the computer simulation campaign, Design of experiment methods (optimal space-filling design among others) were employed instead of exhausting full factorial (parametric) design. Response surface models of major aerodynamic coefficients (lift, drag, pitching moment) at predicted maximum lift coefficient ( C L max) point allowed to narrow down search space and identify several candidates for optimal configuration to be checked experimentally. Wind tunnel tests campaign confirmed the major trends observed in computational fluid dynamics derived response surface contour plots. For the optimum aerodynamic configuration, chosen experimental C L max is over 3.9, which is a 10% increase over the baseline (initial slat and flap positions) case. In parallel, the maximum lift-to-drag ratio gain at that point was almost 19%. The research outlined in this paper was conducted on behalf of the aircraft production company and its results will be applied in a newly designed transport aircraft.

The chapter focuses on explaining the construction of author's own engineering-level model which calculates energy production based on historical water level and flow rate readings as well as economic factors such as net present value of the proposed investment on the example of a HPP on the Wkra River. The model methodology assumes the identification of location's hydrological features and translates them into a set of contingency scenarios. Various internal costs, such as maintenance or labor costs, related to normal HPP activity and taxation are discussed and incorporated into the economic part of the model. Test case results indicate that for a series of good years in terms of water flow and electricity production, full repayment of initial investment costs is possible after less than three years. Results for the chosen modernization parameters indicate that within 10 years of installing a new turbine, even the most pessimistic case would bring added value to the real estate valuation.