Data-Driven Multiobjective Optimization of Wave-Packets for Near-Field Subsonic Jet Noise

Abstract

Aeroacoustics of innovative aircraft cannot disregard the development of low-order models for the jet noise source, which are essential to assess the propulsion–airframe interactions from the conceptual design stage. The main scope of this work is to provide a noise source model that can be coupled with relatively low computational cost methods for aeroacoustic scattering. To this end, this paper presents for the first time a multiobjective optimization of the zeroth-mode wave-packet in the jet near field. The importance of calibrating the model with near-field pressure data stems from the fact that in new aircraft, the engine nacelles are typically positioned at a few diameters from the wing or fuselage. In this work, the near field of a high subsonic jet at a Mach number of 0.9 is represented as a cylindrical surface radiating the pressure disturbances of a wave-packet source, which is optimized using large-eddy simulation data from three lines at different radial distances. The optimized model has been tested at Strouhal numbers between 0.25 and one, and the optimized solutions have been chosen using a Pareto-ranking criterion considering the wave-packet prediction over an extra line. A good agreement is achieved between the reference data and model predictions for multiple near-field radial distances.

An Extensive Near-Field Noise Prediction of a Subsonic Jet Using Data-Driven Surrogate Model Based on Neural Networks

“…Specifically, the LESs were carried out using grids containing a number of points varying between 250 million and 1 billion, with low-dissipation schemes and relaxation filtering as a sub-grid dissipation model [19]. More useful details on the LES can be found in [5,[20][21][22][23].…”

“…However, due to proximity to the jet flow, the near-field fluctuations might be influenced by the rotational hydrodynamic pressure field. Within this zone, the predominant kinetic energy of fluctuations is associated with coherent structures along the azimuth, contributing to nonlinear effects in the evolution of wave packets [5]. Hence, considering the highlighted complexity, accurately predicting the noise source of high subsonic jets remains a challenging task.…”

Subsonic installed Jet noise scattering prediction using BEM and near-field-data-optimized Wave-Packet model

“…al. [33,34] is followed and further extended. A wave-packet describing the pressure fluctuations by a free jet is obtained by optimizing its parameters from near-field data on co-axial lines at several radial distances from the jet axis, namely 𝑟/𝐷 = 0.5, 1, 2 and 2.5, and on a far-field polar arc, 𝑟/𝐷 = 75.…”

“…al. [33,34] followed the approach introduced by Papamoschou [22,[27][28][29], calibrating the model parameters on near-field large eddy simulations (LES) data of a high-speed subsonic isothermal jet. The mentioned paper presents a multi-Strouhal number analysis optimizing the wave-packet source model separately for each value in the set 𝑆𝑡 𝐷 = 0.25, 0.5, 0.75 and 1 and using pressure data from the numerical database for the dominant axisymmetric azimuthal mode.…”

Recent Advances in Airfoil Self-Noise Passive Reduction

“…Noise reduction is crucial for passengers, cabin crew, and residents for reasons such as safety, performance, environmental impacts, regulatory compliance, and customer experience [2]. Today, the noise generated by the interaction between the airflow and different parts of the airframe is increasingly important [3,4]. Typical examples of this type of noise include the noise created by airfoils and other lifting surfaces, as well as the noise from the engine fan blades.…”