Project

MONNALISA Project. Modelling Nonlinear Aerodynamics of Lifting Surfaces.

The performance-improvement objectives sought in the Clean Sky 2 Joint Undertaking requires a departure from conventional empennage configurations and technologies that constitute the current state of the art in aircraft design. An “Advanced Rear End” component for the forthcoming generation of ultra-efficient aircraft might consist of a very compact rear fuselage and tail surfaces with planforms significantly different from those currently used in terms of aspect ratio, taper ratio and sweep angle.
In this project, we aim at developing and validating an innovative, physics-based low-order method to predict the non-linear aerodynamic characteristics of lifting surfaces with controls whose geometry could significantly differ from the usual ones. The development and validation of the method relies on a high-resolution database scanning the extensive space of design parameters required in the call: sweep angle, aspect ratio, taper ratio, dihedral angle, shape of the leading edge and presence of ice. A recently validated approach, based on the most advanced techniques of uncertainty quantification, guarantees the reliability of the database of the aerodynamic characteristics that will drive the development of the method. The aerodynamic database will efficiently mix highly accurate experimental results with state-of-the-art, high-fidelity numerical simulations and lower fidelity simulations.

The success of the project is guaranteed by the scientific quality and reliability of the partners in the consortium that have extensive experience in aerospace research projects, by state-of-the-art experimental facilities and aerodynamic-simulation open-source codes, and by a judicious use of subcontracting.

MONNALISA Project

Description of Work

Within the MONNALISA proposal, five work packages (WP) have been planned to meet all the requirements of the project. The work plan is based on one management work package (WP1) divided in two tasks that will deal with the coordination and the administration of the project and dissemination/exploitation, and four more specific work packages that will deal with technical activities, as shown hereafter.

WP2 is dedicated the design of experiments and high-fidelity simulation with uncertainty quantification (INRIA).

WP3 is dedicated the design and manufacturing of the wind-tunnel models (MTH).

WP4 is related to wind-tunnel testing and high-fidelity simulations to produce the aerodynamic database (POLIMI).

WP5 is devoted to the multi-fidelity modelling of non-linear aerodynamics (POLIMI).

The Concept

The Advanced Rear End work, in the WP1.2 of the Cleansky2 IADP LPA Prototype 1 “Advanced Engine and Aircraft Configurations”, is focused on conceptual and aerodynamic topics, providing a transverse support in the synthesis and evaluation of the demonstrator and focusing on technology items aiming to the reduction of the size, weight and drag of the Rear Fuselage. In this context, the MONNALISA project will develop an accurate, physics-based low-order model for predicting the nonlinear behaviour of tail planes to enable the optimisation of nonconventional rear ends that will characterise next-generation Large Passenger Aircraft.

The concept that we propose to address the Topic is based on the following major points:

The model will be built upon low fidelity aerodynamic methods integrating state-of-the-art and innovative techniques to predict the maximum lift of a tail plane with sweep and dihedron angles.
The model will be developed and calibrated using a novel database of the aerodynamic performance of tail planes covering a large interval of the design parameters, sweep angle, aspect ratio, taper ratio, dihedron angle and four different shapes of the leading edge and ice accretions. The effective selection of the elements of the systematic series to cover the design space of trapezoidal tail surfaces is a critical decision as it will affect the cost of the wind tunnel testing and the overall accuracy of the database. In this project, we will use an innovative strategy, based on novel techniques for uncertainty quantification (UQ) to create the systematic series of numerical and experimental results that minimises cost and time, while guaranteeing that the design space is effectively covered in terms of aerodynamic behaviour with a prescribed level of accuracy.
Uncertainty quantification and Bayesian calibration will also be used to build a correction function, which will improve the accuracy of the model over the entire range of the parameters.

The Goals

The objective of the present project is to contribute to the design of a demonstrator of the Advanced Rear End of advanced and ultra-advanced, short/medium/long range civil aircraft. The contribution of the present project to this goal is to the development of numerical methods for the prediction of the nonlinear aerodynamic characteristics of lifting surfaces, of the type used in the tails of civil commercial aircraft. In this respect, the consortium confirms that the project complies with applicable international, EU and national law and the research activities have an exclusive focus on civil applications.

The ultimate goal of this research project is to develop a low-order numerical method based as far as possible on physical phenomena to match the results of the wind tunnel tests of the systematic series of geometries of tails of civil commercial aircraft, possibly including small correction factors.

Intermediate objectives, which are functional to achieving the main objective are:

To develop a systematic series of wind tunnel tests of several models of tails of civil commercial aircraft covering a wide range of planform parameters, with and without simulated ice shapes. The choice of the test parameters will be driven by advanced Uncertainty Quantification techniques coupled to high-fidelity simulation.
To integrate the experimental database with a systematic series of numerical simulations of tails of civil commercial aircraft in order to increase the resolution of the database with respect to the control parameters. The proposed approach would permit to detect regions of the parameter space for which experimental measurements of tails of civil commercial aircraft can be substituted by high-fidelity numerical simulations.
To develop bayesian-based calibration methods using the full database of the aerodynamic performance of tails of civil commercial aircraft in order to extend the prediction of the maximum lift coefficient and hinge moment of tail surfaces given by the low-order numerical technique to an arbitrary Reynolds number.
To use the developed database to build an error function, which will correct the outcome of the low-order numerical method.

Official Data

Type of action: CS2-RIA
Project number: 101008257

Starting Date:

01.01.2021

Duration (months):

WP1 | Management (leader: POLIMI)

This WP is divided in two Tasks. This work package covers the issues related to the administration of the project, e.g. cost and time controlling, management of meetings and reports, communication with the European Commission, with the Topic Manager and among the partners. The WP will also ensure adequate dissemination of the project results. Scheduling will be monitored through dates of the activities ensuring that all project deliverables are delivered in time and in accordance with expectations. Management will consider eventual recovery actions to mitigate risks that could have an impact on the outcome of the project and on possible delays.

WP2 | Design of experiments, UQ methods and high-fidelity CFD analysis (leader: INRIA)

This work package is divided in three Tasks. It is devoted to the application of advanced UQ techniques and high-fidelity CFD to assess the predictive capability of high-fidelity CFD. This analysis allows drastically reducing the number of informative experiments to be performed in Task 3.

WP3 | Wind-tunnel model design and manufacturing (leader: MTH)

In this work package, a parametric tail-plane model is produced to be employed in other work packages to produce computational grids. Moreover, wind-tunnel models spanning the parameter space are designed and manufactured. Finally, the shape of produced models is measured to verify that its precision is within the prescribed tolerances.

WP4 | Aerodynamic database generation (leader: POLIMI)

This work package is devoted to the generation of a database of the aerodynamic performance and characteristics of the tail plane. It is organised in two Tasks. The first one is related to the wind-tunnel testing activity, the second one is related to the high-fidelity CFD simulations. Both techniques will complement each other in the construction of the database under the guidance of the results obtained in WP2, allowing a significant saving in costs for model production.

WP5 | Physics-based modelling of nonlinear aerodynamics (leader: POLIMI)

This WP is divided in tree Tasks. This work package covers the issue of develop a fast and reliable low order physics based aerodynamic method for the prediction of the maximum lift coefficient and control hinge moment of any lifting surface within the range of parameters covered by the systematic series of geometries tested in the wind tunnel. The model will be implemented leveraging the open-source solver DUST.

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