The proposed activities directly contribute to the fundamental objectives of SE2A as defined in the ful proposal from February 2018. The proposed simulation process will help to identify and determine the medium and long-term (year 2050) potential for eliminating the carbon footprint of future air transport operation under consideration of aircraft noise. Social and economic constraints can directly be associated with community noise annoyance due to aircraft operation. The selected simulation process will enable to assess comprehensive criteria and metrics and to serve as a basis for decision-making between ICA-A, ICA-B, and ICA-C. For example, the proposed process is an essential prerequisite to assess the noise of any new vehicle and flight procedures as developed in ICA-B (under 3.4.2.5 Design methodology and assessment of aircraft) and noise shall be included as a design constraint in the planned Design Engineering Engine (DEE).
The overall process for the evaluation of novel aircraft and technology is depicted here. The process is comprised of ICA-A.1, ICA-A.2, and ICA-A.3.
Various research activities in the field of low-noise aircraft design and flight trajectory optimization are ongoing at universities and major research organizations, e.g., NASA activities in the Environmental Responsible Aviation Program [1]. NASA has developed a tool ANOPP for parametric noise prediction back in the 70ies and is ever since updating and modifying it to account for recent findings and innovations toward low-noise vehicle concepts [2]. The focus lies on the vehicle design and flight procedures are currently not adapted and optimized. ANOPP2, i.e., the scientific variant of ANOPP, can be applied to study promising low-noise architectures, e.g., a hybrid wing body [3, 4]. A summary of low-noise activities toward quiet subsonic transport concepts is summarized in Ref. [1]. The latest application results to tube-and-wing architectures are presented in Refs. [5, 6]. Consequently, these advanced vehicles are then integrated by Georgia Tech into the airspace to identify the impact on airport capacity and overall scenario noise. Yet, this integration is a subsequent process without feedback loop back to the aircraft design or flight procedure, see Ref. [7, 8]. Furthermore, the challenge with respect to such an integration is not to neglect important information or actual physics due to simplification and integration of single flight events into large simulation scenarios. Besides NASA, ONERA has published about their activities toward low-noise air transport concepts. The focus thereby lies on the overall impact on a scenario level, i.e., the environmental impact of novel vehicles on the air transport system, see Refs. [9, 10, 11, 12].
References:
Activities in the area of low-noise aircraft design and low-noise flight optimization have been initiated around 2008 and are still ongoing. Based on parametric models for engine and airframe noise, a tool for overall aircraft noise immission prediction has been developed [1]. The tool has been furthermore integrated into aircraft design synthesis codes and distributed simulation environments to finally enable an automated assessment of novel vehicles and flight procedures [2, 3]. Noise predictions can now automatically be added as design constraints within the aircraft design process, see Ref. [4]. Additional noise sources have been integrated and the tool has constantly been updated for additional applications, e.g., see Refs. [5], [6] and [7]. Yet, introduction of new technologies, e.g., advanced propulsion integration, can create new noise sources that must be carefully modelled for reliable application in aircraft design. Recent applications include short take-off and landing vehicles with active high-lift concepts [8, 9] and the assessment of ultra high bypass ratio engines on board of conventional and low-noise aircraft architectures, see Refs. [6] and [10], respectively. Investigation of the annoyance of novel vehicles along their flight procedures has been initiated in 2015 [11] and an auralization process with dedicated listening tests has been realized in 2018, see Ref. [12]. The first attempt to assess uncertainties associated with the noise prediction is described in Ref. [13]. A recent overview on all related activities and on noise assessment in general is described in Ref. [14].
Previous work does not include any cabin noise assessment which might become an essential design objective in the context of novel engine integration concepts. This issue is adressed in ICA-A2.3.
References:
Exemplary, a DLR low-noise aircraft concept is depicted here. Based on previous studies, new vehicle will be designed and assessed in the context of the Cluster. Another design criteria for novel vehicles is the reduction of gaseous emissions and the overall climate effect of aviation. Promising solutions could feature electrification of the propulsion system or application of alternative fuels, socalled bio fuels.
Initial work in the Cluster context demonstrates the feasibility of a multi-level, multi-fidelity approach. The approach furtermore facilitates the assessment of new aircraft technologies within an entire airport scenario as proposed for the SE2A cluster, see Cluster reference [1] (under Publikationen). A first application of this evaluation process to recent DLR low-noise aircraft is presented in Cluster reference [2] (under Publikationen).
Most recent activities focus on the aircraft design of low-noise SE2A vehicles under consideration of gaseous emissions. Furthermore, activities with international partners Empa and University of Alamaba have been initiated in the area of prediction uncertainties. The activity is coordinated by ICA-A2.1 and cluster partner Prof. Uli Römer (involved in ICA-B2.3 and ICA-C1.1).
The key requirement to introduce any sustainable air transport solution, is to ensure the stakeholders acceptance of new technologies and novel aircraft along their individual flight procedures. Obviously, the exterior aircraft noise (immission) plays a major role for the acceptance. Consequently, each fly-over event has to be simulated in an adequate level of detail in order to assess the entire problem. Within the cluster, new simulation capabilities are required to simultaneously assess environmental, economic and social criteria, e.g., noise exposure versus life-cycle analysis. In this context, a cooperation with Prof. Zoltan Spakovszky from the Massachusetts Institute of Technology (MIT) is established. Prof. Spakovszky is a well known expert in the area of low-noise aircraft design [1] and novel technologies in the context of electrification in aviation [2]. He acts as a double supervisor for the ICA-A2 PhD candidate and thereby supports the identification and assessment of promising novel technology and vehicle designs to ultimately reach the SE2A targets. The overall target of the cooperation is to realized and ensure a feasible and comprehensible comparison of different aircraft technologies as developed in the SE2A, i.e., realization of a decision-making support in the context of sustainable air transport solutions
Prof. Zoltan Spakovszky,
Massachusetts Institute of Technology (MIT),
Boston, USA
Selected references:
Dr. Lothar Bertsch
Institute of Aerodynamics and Flow Technology, DLR Göttingen
+49 551-709-2473
