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September 25, 2022

KEDIMA

Commercial aircraft and aviation in general face in flight the appearance of turbulent fields, which requires changes in airplane trajectory in order to avoid as much as possible the danger to aircraft and passengers.

24
June, 2022
Dată început proiect
20
June, 2024
Dată sfârșit proiect

Technical details

UEFISCDI Program: National Research-Development and Innovation Plan 2015 – 2020 (PNCDI III)

Program 2: Increasing the competitiveness of the Romanian economy through research, development and innovation

Subprogram 2.1: Competitiveness through research, development and innovation

Project title: Innovative method of measuring the turbulence in wind tunnel based on Kolmogorov concept of energy dissipation magnitude with application in flight forecast

Project Code: PN-III-P2-2.1-PED-2021-4147

Acronym: KEDIMA

When ICAO Amendment 75 to Annex 3 became applicable on 18 November 2010, routine voice reporting of weather, a natural consequence of the subjectivity of those reports, was no longer required. To address these deficiencies, an in situ turbulence reporting algorithm based on ICAO standard EDR index (eddy dissipation rate) began to be implemented. During these years, the calculation method of this indicator has not yet stabilized firmly, new and new modifications of the algorithm are introduced in order for this direct calculation on the plane to improve. It is important for the conception of the project KEDIMA to emphasize that, for the airplane in turbulence field, for now the calculation of EDR it is not done on the basis of the well-known definition of turbulence energy given by Kolmogorov, but it is estimated based on the vertical component of the air speed, or based on the vertical component of the resulting acceleration of the aircraft.  The approach is effective, but remains an approximate one, maybe also because it wants to be independent from the airplane.  Thus, on the one hand, EDR is dependent on the aircraft that determines and transmits these indicators, to be useful not only as a diagnosis of what happens to the source aircraft, but also as a forecast, for the transmission of information, to other aircraft which would enter the respective turbulence field. On the other hand, EDR transmitted in situ is a surrogate of the concept of turbulence, since it is not calculated starting from the basic concept (of Kolmogorov). Thus, the purpose of the project is to demonstrate that the basic EDR index of atmospheric turbulence intensity can be measured and calculated in wind tunnel according to the basic Kolmogorov concept.

Results – Phase I

Phase 1 “Development of the theoretical basis and logistics for the demonstration of the method” includes the following activities:

Act. 1.1 – Evaluation of the methods of analysis and identification of turbulence intensity for aviation diagnosis and forecasting. State of the art;

Act. 1.2 – Theoretical study of the parameters to be measured in WT for the evaluation of turbulence characteristics (EDR, Richardson number).

Act 1.3 – Development of a general test program in WT for measuring and calculating EDR and Ri.

Act. 1.4 – Purchase of equipment.

Act. 1.5 – Dissemination of results. Publication of works, participation in national or international conferences.

Turbulence is a cascade process, through which kinetic energy is transferred from large eddies to small eddies, where it dissipates in heat, and the rate of transfer from large to small is the same as the rate of heat dissipation in the smallest eddies. Navier-Stokes motion of a fluid

it is subject to viscous and inertial constraints, the latter being given by the term (u ·)u, responsible for the generation of turbulence, i.e., continuous and disordered variations of physical quantities (velocity, position, energy). The heat transfer and the frictional tension inside the flow cannot be measured directly, but only indirectly, by means of the measurement of speed and temperature fluctuations, and by means of their correlations.

Table 1: Correspondence between the levels of intensity (severity) of the turbulence phenomenon and the values of the parameter EDR [m2/3/s], for transport aircraft, medium class* moving in typical flight conditions (altitude, speed, weight ).

ZEROLIGHTMODERATESEVEREMOG**
conf. [18]≤ 0.15> 0.15 & ≤ 0.22> 0.22 & ≤ 0.34> 0.34> 0.22
conf. ICAO 2001 [19]≤ 0.10> 0.10 & ≤ 0.30> 0.30 & ≤ 0.50> 0.50> 0.30
conf. ICAO 2007 [17]≤ 0.10> 0.10 & ≤ 0.40> 0.40 & ≤ 0.70> 0.70> 0.40
conf. ICAO2020 [20] 0.10> 0.10 & 0.20> 0.20 & 0.45> 0.45> 0.20
conf. [21]≤ 0.10> 0.10 & ≤ 0.30> 0.30 & ≤ 0.50> 0.50> 0.30
conf. [22]≤ 0.14> 0.14 & ≤ 0.34> 0.34 & ≤ 0.54> 0.54> 0.34
conf. [23]≤ 0.03> 0.03 & ≤ 0.07> 0.07 & ≤ 0.16> 0.16> 0.07
conf. [24]≤ 0.14> 0.14 & ≤ 0.23> 0.23 & ≤ 0.46> 0.46> 0.23
conf. [25]≤ 0.14> 0.14 & ≤ 0.20> 0.20 & ≤ 0.41> 0.41> 0.20

* aircraft are considered to be part of the heavy class if their mass at take-off is greater than or equal to 136000 kg, they are part of the medium class if at take-off their mass is greater than 7000 kg, but less than 136000 kg and are part of from the light class if at take-off their mass is less than or equal to 7000 kg [26].

**MOG = “moderate or greater”, turbulence of moderate or greater intensity.

Results dissemination

1. New strategy for the safety and comfort of the passengers and aircraft crew during atmospheric turbulence – D. Enciu, I. Ursu, G. Tecuceanu, 7th European Conference on Structural Control (EACS 2022), 10-13 July 2022, Warsaw, Poland

Abstract

An airplane trip can be psychological terrifying for any traveler. If, during the flight, the airplane meets a turbulent air front, then the scenario is perfect for a Hollywood movie, and the panic among passengers increases proportionally with the severity of the turbulence. In this paper, a new approach of the turbulence mitigation methodology is proposed based on a solid background using an active control vibration. The experimental model is represented by a realistic, elastic airplane wing model controlled by an electric linear servoactuator. The mathematical model is completed by numerical simulations and experiments in the subsonic wind tunnel upgraded with a turbulence generator. The qualification of an emergent technology of this type will have double impact: for the passengers – safety and mental comfort increasing given by the significant reduction of the dynamic effects produced by the turbulent field; for the airplane – weight optimization based on the loads control generated by the atmospheric turbulence.

2. On the evaluation of turbulence parameters in the Wind Tunnel – D. Enciu, I. Ursu, G. Tecuceanu,  International Conference of Aerospace Sciences „AEROSPATIAL 2022”, 13-14 October 2022, INCAS, Bucharest, Romania

Abstract

Commercial aircraft and aviation, in general, face in flight the appearance of turbulent fields, which requires immediate changes in airplane trajectory in order to avoid as much as possible the danger to aircraft and passengers. Up until 2010, the International Civil Aviation Organization (ICAO) [1] considered AIREPs (an automated report of weather conditions encountered during flight) and PIREPs (pilot report about weather conditions encountered during flight) a turbulence intensity indicators. In order to avoid the subjectivity of those reports, which were dependent on the type of aircraft, air speed, pilot experience, the reaction of the crew and the movement of unsecured objects around the cabin, an in situ turbulence reporting algorithm based on ICAO standard EDR index (eddy dissipation rate) has been considered [2]. The EDR index is defined as the cubic root of the turbulence energy per unit time and mass [3]. In turbulent motion there is a cascading process, through which kinetic energy is transferred from the larger eddies to the lowest eddies, where it dissipates in heat, and the energy transfer rate from the larger eddies to a smaller ones is the same as the rate of energy dissipation in heat in the smallest eddies. This is how the process of dissipation and decay of fractal-generated turbulence takes place. The theoretical background is based on the Kolmogorov approach [4], [5]. The determination of the order of magnitude of the energy dissipation during the turbulent motion has as reference the procedure described in [6]. The intensity of turbulence will be identified in the INCAS subsonic wind tunnel (WT). The turbulence is produced by a passive turbulence generator [7]. A Big Data volume is in this way obtained and becomes the basis of statistical calculations for turbulence diagnosis and forecasting.

3. Towards improving passangers safety and comfort based on turbulence test in aerodynamic tunnelD. Enciu, I. Ursu, The 8th Conference of the Sustainable Solutions for Energy and Environment (EENVIRO 2022), 16-20 October, UTCB, Bucharest, Romania

Abstract

First, the article outlines the elements of an ongoing research project, aiming to demonstrate that the basic ICAO standard EDR (Eddy Dissipation Rate) index of atmospheric turbulence intensity, defined as the cubic root of the turbulence energy per unit time and mass, can be measured and calculated in Wind Tunnel (WT) according to the basic Kolmogorov concept. This involves showing that EDR index calculated in WT, taking a sufficient number of velocity measuring points, can be an objective measure of turbulence intensity, independent of the body immersed in the fluid. Secondly, it is shown that these measurements are accompanied by intermediate active vibration control tests. For this purpose, a Turbulence Generator was built and installed in the WT and an intelligent wing model with implemented LQG active control was introduced in the WT. These two procedures, complementary in substance, aim to demonstrate the consistency of the flight approach based on the objectivity of this ICAO standard EDR index and the vibration reduction methodology in a turbulent atmospheric environment.

Informații suplimentare se pot obține la sediul I.N.C.A.S. Bucureşti
Research & development

Dr. math. Daniela Enciu

Email:incas@incas.ro
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