B05: Cabin noise of integrated and distributed propulsion

Discipline Acoustics

Bringing acoustics into the preliminary design process to ensure a comprehensive assessment, is one of the major objective of the project. The effect of highly integrated transport aircraft on cabin noise is investigated. In the examinations, a clear focus is put on SynTrac’s mission of a cross-disciplinary, cross-system integration. The sound fields are made accessible in early design phases through appropriate mid-fidelity models of the entire aircraft. For this purpose, a configuration-specific selection of required modelling aspects as well as a design-loop-appropriate numerical solution are investigated. The novel concept require specific reductions of wave-resolving, high-fidelity FE computations.

Motivation

Which vibroacoustic modelling aspects are potentially influenced by preliminary design parameters and must therefore be addressed in a wave-resolving cabin noise simulation and which solution strategies for the identified required models finally meet the integration requirements of the holistic design?

  • Integrate cabin acoustics into the preliminary design process of highly integrated transport aircraft
  • Create the basis for comprehensive assessment
  • Provide acceptance of new technologies from the acoustic point of view
  • Systematic prepare and reduction of vibroacoustic high-fidelity models for a holistic preliminary aircraft design

Objective

  • An appropriate solution – appropriate for early design – is implemented by using augmented models with selected configuration-specific modelling aspects.
  • Implementation and investigation of efficient solution strategies:
    1. Parallel multi-frontal LU decomposition vs. iterative solvers using block preconditioners with physics-based domains
    2. Recycling techniques
    3. Rough design decisions based on coarsely meshed low frequency solutions
  • A mid-fidelity model able to calculate sound pressure level inside the cabin, is delivered to A06 demonstrating the integration into the holistic design approach.

Approach

The approach is to integrate the cabin acoustics into the preliminary design process by implementing modelling synergies. Therefore, the data concept developed with A06 will be discussed to realise a virtual demonstrator at the end of this funding period. To accomplish this objective, it is necessary to identify and model relevant sources and paths. For aircraft configurations 1a and 2a, each with different sound transmission characteristics, parameterised vibroacoustic finite element (FE) models will be developed. The preliminary design for vibroacoustic models should then be expanded based on this data.
This requires an experience- and optimization-based expansion of the available data for the aircraft airframe, trim, and cabin. In the final step, corresponding numerical analyses of complete aircraft configurations should be carried out to implement and analyze efficient solution strategies.

Role in SynTrac

  • High-fidelity models are derived based on preliminary design data from A06 and detailed structural data and loads (back of config. 1a) from B06
  • Structural and flow induced structural loads by method in C04 (config. 2a)
  • Aeroacoustic loads from C05 (config. 1a) and from C06 (config. 2a)
  • Efficient augmented mid-fidelity aircraft modelling with A06
  • Further cooperation: B01, B04, C01

All people involved in the project "B05: Cabin noise of integrated and distributed propulsion"