Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: AAT.2010.4.2.-7 | Award Amount: 3.49M | Year: 2010
Reynolds stress is the most important quantity affecting the mean flow as it is responsible for a major part of the momentum transfer in the wall bounded turbulent flow. It has a direct relevance to both skin friction and flow separation. Manipulation of the Reynolds stress can directly lead to changes in the viscous stress at the wall so as to effectively control the flow for effective flow control. However, there is a lack of current understanding of the inter-relationship between the various flow control devices and the Reynolds stresses in the flow field they produced. An improved understanding can potentially significantly improve the effectiveness of flow control as the Reynolds stresses are closely related to the flow behaviour at the surface for effective separation control or drag reduction. A variety of control devices are available and new ones are invented but which one for what purpose is an open question yet to be fully answered. MARS proposal proposes to reverse that process and consider the long term goal of controlling dynamic structures that influence the Reynolds stress that changes the mean flow. This radical approach recognises we are still some way away from hardware to implement it at flight scales but if successful, would establish a first important step towards our ultimate ambition. The focus of MARS will be on the effects of a number of active flow control devices on the discrete dynamic components of the turbulent shear layers and the Reynolds stress. From the application point of view, MARS provides a positive and necessary step in the right direction wherein it will demonstrate the capability to control individual structures that are larger in scale and lower in frequency compared to the richness of the time and spatial scales in a turbulent boundary layer. MARS will investigate active flow control means rather than passive controls.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: AAT.2013.7-7. | Award Amount: 534.35K | Year: 2013
As mentioned in the Executive Summary of the Strategic Research & Innovation Agenda, Aviation has an important role to play in reducing greenhouse gas emissions as well as noise and local air quality issues. The continuous increase of air passenger transport generates an increasing use of hydrocarbon fuel with excessive emission of CO2 and NOX (greenhouse gases, pollutants and noise). It is well known that commercial aircraft operations impact the atmosphere by the emissions of greenhouse gases and greenhouse gas precursors, and also through the formation of contrails and cirrus clouds. In 2011, during the Aerodays in Madrid, the EC launched the future of Aeronautics in the ACARE Flight Path 2050 Vision for the Aircraft report containing the ambitious goals on the environmental impact with 90% reduction in NOx emissions, 75% reduction in CO2 emissions per passenger kilometer, and the reduction of the noise in by 65%, all relative to year 2000. To achieve the ACARE Strategic Research & Innovation Agenda green aeronautics technologies will play a more and more dominant role in mastering the challenge on Protecting the environment and the energy supply. GRAIN2 Supported Action, based on the same collaborative and win-win spirit introduced in former EU-China GRAIN project, will provide inputs and roadmaps for the development of large scale simulation strategies for greener technologies to meet the above future requirements on emissions, fuel consumption and noise. To reach these targets, green technologies efforts will have to be collected and prospected in three major lines: Air vehicle, Air Transport System and Sustainable Energies. Three folds to be investigated as future greening technologies: 1) Greening the aircraft and the aero engine 2) Greening the operational environment 3) Reducing the carbon foot print of aviation via sustainable alternative fuels
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: AAT-2007-7.0-07 | Award Amount: 663.73K | Year: 2007
The aim of the AEROCHINA2 Coordination Support Action (CSA) is to foster the cooperation between a number of industry, university and research organizations in the aeronautics sector in Europe and China in the field of multi-physics modelling, computer simulation and code validation, experimental testing and design methods for the solution of multi-physics problems of interest to the aeronautic sector. The spectrum multi-physical disciplines considered in AEROCHINA2 which are of interest of European and Chinese partners are Aerodynamics, Structures & Materials, Fluid Dynamics, Aeroacoustics, Active Flow Control and Aero Elasticity. The general strategic objectives of the project are three fold: 1) to identify areas of mutual RTD interest and the clarification of the skills, experiences and capabilities of the Chinese partners in the relevant technological areas of multi-physics analysis and design; 2) to develop concepts of collaboration in those areas between the European and Chinese partners in order to ensure a win-win situation; 3) prepare specific RTD activities that are mature for joint proposals for FP7. These AEROCHINA2 objectives correspond to a more long term preparation necessary for substantial and sustainable win-win cooperation in forthcoming FP7 calls.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: AAT.2010.7-6. | Award Amount: 521.30K | Year: 2010
Aerochina1&2 have been networking projects co-funded by FP7 and AVIC (China) and coordinated by CIMNE. Many of the GRAIN partners have participated in them. These collaborative projects gathered experts on the two Europe (13) and China (17) sides to foster cooperation and debate future trends in the field of integrated multi physics modeling, computer simulations and code validation, experimental testing and design methods for the solution of multi physics problems of interest to the aeronautic sector. The outcomes of these two projects provided specific and mature RTD activities and teams for FP7 EU-China Coordinated calls. The main objectives of GRAIN are to identify and assess the future development of large scale simulation methods and tools needed for greener technologies reaching the Vision 2020 environmental goals. GRAIN will prepare the R&T development and exploitation with new large scale simulation tools used on distributed parallel environments to deeper understand and minimize the effects of aircraft/engine design on climate and noise impact. High-performance and innovative methodologies and algorithms must also be designed to take full benefit of high-performance computer infra structures existing or quite soon available in Europe and China. The participating institutions will focus on future collaborative applied research concerning modeling, experiments, simulation, control and optimization for greener aircraft and engines technologies including: emissions, drag and noise reduction and green materials with an emphasis on multidiscipline approaches for environmentally friendly aircraft. These collaborations will be dedicated to 3-D and these configurations will imply the use of high performance computing facilities that are now available and upcoming in both Europe and China. New developments will be investigated concerning innovative methodologies on robustness and uncertainty for greener aircraft applications.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: AAT.2010.4.1-8. | Award Amount: 3.68M | Year: 2010
This proposal is in response to the call for EU and China collaboration on casting large Ti structures. The consortium consists of 7 EU and 7 Chinese partners. This proposal aims to make a step-change for casting of large Ti components by overcoming some key challenges in the casting process. Such a step-change is critical if the production of large Ti components is to meet the requirement in cost reduction by endusers, the requirement of CO2 reduction and raw material wastage reduction in every step of component manufacturing process by the endusers and by the society. This step change will involve the development of the centrifugal casting process by which the filling of thin sections of large Ti structures will be improved so that significantly fewer and smaller defects will be present in the component and a significantly higher production yield rate will be achieved. Further development will be carried to improve the gravity casting process which is important for casting asymmetrical components such as Ti airframes. Those developments will be closely coupled with the development of computer modelling in terms of better understanding and predicting liquid filling of the mould, defect formation and distribution, control of the dimensional accuracy of the cast component together with the development of a stronger wax and optimum ceramic mould material if required in order to meet the component dimension tolerance specified. The microstructure and mechanical properties including that of heat treated and welded castings must be optimised. If successful, this project will lead to significant cost reduction in producing large Ti components; removal the USA monopoly of supply of aeroengine Ti casings and significant reduction of CO2 and of Ti raw material wastage incurred in current manufacturing processes. It will also lead to more application of light Ti structures in aerospace and space, thus weight and fuel reduction by making Ti structure commercially viable.
Liao H.,Chinese Aeronautical Establishment
Journal of Computational Physics | Year: 2016
The direct differentiation and improved least squares shadowing methods are both developed for accurately and efficiently calculating the sensitivity coefficients of time averaged quantities for chaotic dynamical systems. The key idea is to recast the time averaged integration term in the form of differential equation before applying the sensitivity analysis method. An additional constraint-based equation which forms the augmented equations of motion is proposed to calculate the time averaged integration variable and the sensitivity coefficients are obtained as a result of solving the augmented differential equations. The application of the least squares shadowing formulation to the augmented equations results in an explicit expression for the sensitivity coefficient which is dependent on the final state of the Lagrange multipliers. The LU factorization technique to calculate the Lagrange multipliers leads to a better performance for the convergence problem and the computational expense. Numerical experiments on a set of problems selected from the literature are presented to illustrate the developed methods. The numerical results demonstrate the correctness and effectiveness of the present approaches and some short impulsive sensitivity coefficients are observed by using the direct differentiation sensitivity analysis method. © 2016 Elsevier Inc..
Liao H.,Chinese Aeronautical Establishment
Nonlinear Dynamics | Year: 2016
A novel method is presented to calculate the sensitivity gradients of the largest Lyapunov exponent (LLE) in dynamical systems. After the elimination of the discontinuity of state perturbation vector, the augmented system of differentiation equations is constructed to govern the time evolution of the LLE. To overcome the ill-posed property of the sensitivity problem associated with the augmented differentiation system, the improved least squares shadowing approach is developed. The simple algebraic formula depending on the final state value of the Lagrange multipliers is deduced from the discretization representation for the first-order optimal conditions of the improved least squares shadowing formulation. The LU factorization technique is introduced to solve the set of discretized linear equations, resulting in a better performance of the convergence problem and computational expense. The correctness and effectiveness of the present approaches are validated. © 2016 Springer Science+Business Media Dordrecht
Liao H.,Chinese Aeronautical Establishment
Journal of Fluids and Structures | Year: 2015
A method is proposed to calculate the periodic solutions of piecewise nonlinear systems. The method is based on analytical derivation of nonlinear multi-harmonic equations of motion. Since periodic variations of nonlinear forces are characterized by different states, the vibration cycle is broken into sequential transition intervals according to the instant sets of state transitions. Analytical formulations of the harmonic coefficients of the nonlinear forces and its derivatives with respect to the harmonic coefficients of displacements are developed. Sensitivities of the harmonic coefficients of periodic solutions are determined for constructing explicit expressions for vibration amplitude levels as a function of structural parameters. Numerical investigations of the limit cycle oscillations and its sensitivities of an airfoil with different piecewise nonlinearities have been performed. The results show that the developed method is capable of determining the periodic solutions and its sensitivities with respect to the structural parameters. In order to guarantee time continuity of the nonlinear force, for the hysteresis model it is not right to track the periodic solutions by using the preload or freeplay as the continuation parameters. © 2015 Elsevier Ltd.
Liao H.,Chinese Aeronautical Establishment |
Sun W.,Chinese Aeronautical Establishment
Nonlinear Dynamics | Year: 2013
An original method based on the proposed framework for calculating the maximum vibration amplitude of periodic solution of non-linear system is presented. The problem of determining the worst maximum vibration is transformed into a non-linear optimization problem. The harmonic balance method and the Hill method are selected to construct the general non-linear equality and inequality constraints. The resulting constrained maximization problem is then solved by using the MultiStart algorithm. Finally, the effectiveness of the proposed approach is illustrated through two numerical examples. Numerical examples show that the proposed method can, at much lower cost, give results with higher accuracy as compared with numerical results obtained by a parameter continuation method. © Springer Science+Business Media Dordrecht 2012.
News Article | September 29, 2016
SHANGHAI (Reuters) - NASA has signed an agreement with the Chinese Aeronautical Establishment (CAE) to cooperate on research that will help China's airports improve their management of air traffic, the U.S. space agency said late on Wednesday.