Wolfgang Heinze

Multidisciplinary Integrated Preliminary Design Applied to Unconventional Aircraft Configurations

A preliminary aircraft design tool is presented as a means of performing multidisciplinary, integrated preliminary design of unconventional aircraft configurations. Higher fidelity numerical methods for some of the involved disciplines are discussed as key elements of this process. A noise propagation module is described as a first step toward introducing aircraft noise analysis into the preliminary design process. Application of the tool to a specific unconventional aircraft concept is shown. The results of this study provide an understanding of why multidisciplinary design analysis and optimization, as well as higher fidelity methods, are required for the design of unconventional aircraft configurations.

Multidisciplinary Integrated Preliminary Design Applied to Future Green Aircraft Configurations

The Preliminary Aircraft Design and Optimization tool (PrADO) is presented as a means of performing multidisciplinary, integrated preliminary design of unconventional aircraft configurations, with a focus on green aircraft concepts. High fidelity numerical methods for some of the involved disciplines are discussed as key elements of this process. A noise propagation module is described as a first step towards introducing aircraft noise analysis into the preliminary design process. Application of the tool to a specific Low Noise Aircraft (LNA) concept is shown. Although the structural weight of the LNA is significantly higher than that of a conventional reference aircraft designed for the same transport mission, the results of the design analysis indicate that the LNA can still achieve advantages in terms of direct operating costs if certain economic and operational conditions are met.

Improved Representation of High-Lift Devices for a Multidisciplinary Conceptual Aircraft Design Process

*† ‡ A methodology for improving the quality of high lift system performance prediction within a multidisciplinary preliminary design process is presented. The high lift system geometry is explicitly modeled and a multiple lifting line method is used to compute its aerodynamic characteristics. Computation times are suitable for use in a preliminary design process, and the results for several test cases show good agreement with wind tunnel and/or high fidelity numerical data. In addition, the method allows for further enhancement by using non-linear airfoil polars for interpolation, improving drag prediction and introducing some degree of non-linear aerodynamic behavior.

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Preliminary design studies indicate that a cruise-efficient short takeoff and landing aircraft has enhanced takeoff performance at competitive direct operating costs when using high-speed propellers in combination with internally blown flaps. The original tractor configuration is compared to an over-the-wing propeller, which allows for noise shielding. An additional geometry with partially embedded rotor similar to a channel wing is considered to increase the beneficial interaction. This paper shows the aerodynamic integration effects with a focus on climb performance and provides an assessment of the three aforementioned configurations for a simplified wing segment at takeoff conditions. Steady Reynolds-averaged Navier–Stokes simulations have been conducted using an actuator disk model and were evaluated based on the overall design. Interacting with the blown flap, the conventional tractor propeller induces large lift and drag increments due to the vectored sliptream. Although this effect is much smaller...

Application of an Aircraft Design-To-Noise Simulation Process

System noise has been integrated as an additional design objective within conceptual aircraft design. The DLR system noise prediction tool PANAM accounts for individual noise sources depending on their geometry and operating conditions. PANAM is integrated into the existing aircraft design framework PrADO from the Technical University of Braunschweig in order to realize a design-to-noise simulation process. In addition, a ray-tracing tool from DLR, SHADOW, is incorporated into the simulation framework in order to account for structural engine noise shielding. The overall simulation process is then applied to identify promising low-noise aircraft concepts. The presented application aims at fan noise reduction through shielding. For the selected reference aircraft, the fan is a major noise source during both landing and takeoff. It is demonstrated, that the aircraft designers influence on the environmental vehicle characteristics is significant at the conceptual design phase. Usually, a trade-off between extensive engine noise shielding and economical flight performance is inevitable. The new design-to-noise process is well suitable to assess all four measures of ICAOs balanced approach.

Simulation process for perception-based noise optimization of conventional and novel aircraft concepts

Noise from civil air traffic affects millions of people worldwide. Aircraft noise management should be addressed by different principal elements, such as noise reduction at the source and noise abatement operational procedures. To date, usually conventional noise metrics are applied towards the acoustical optimization while noise effects are usually only indirectly accounted for. The objective of this contribution is the optimization of conventional and novel aircraft concepts with respect to their evoked aircraft noise annoyance. The optimization will be based on the perceived sound and the associated annoyance. To do so, virtual aircraft flyovers are auralized based on noise level predictions, i.e. they are artificially made audible. The auralization is accomplished by parametric sound synthe- sis and a 3D spatial audio technique. Short-term noise annoyance is measured through controlled listening experiments in which participants rate the level of annoyance for each auralized flyover. The aircraft design and the flight path are evaluated according to the associated annoyance. The subsequent ranking can be compared to a conventional ranking based on standard noise metrics. The results of such a study will help to identify parameters describing aircraft and flight path parameters that have an impact on noise annoyance. Consequently, these parameters can then be selected for further optimization to reach even lower levels of noise annoyance and not simply reduce standard noise metrics. Ultimately, the main goal of the research is optimizing the noise annoyance of (novel) aircraft along tailored flight paths. This contribution documents the status quo of the joint DLR and Empa activities, i.e., the structure of a pilot study. First results that were obtained while developing the methodology and the test cases within the pilot study are presented.

Robustness Analysis of an Aircraft Design for Short Takeoff and Landing

As part of the Collaborative Research Center 880, preliminary aircraft design activities are carried out for a new class of low-noise cruise-efficient short takeoff and landing (CESTOL) transport aircraft. A corresponding aircraft is quite different from a state-of-the-art commercial aircraft because of the use of a high-lift system with active flow control. The fact that new technologies are not sufficiently understood yet in combination with the assumption of common design data and the use of classical calculation methods expresses itself in uncertainties that are of epistemic character. The robustness of a deterministic CESTOL aircraft design toward parameters such as the necessary engine thrust, direct operating costs, and the maximum takeoff and landing distances is investigated here concerning the mentioned uncertainties. For this purpose, a stochastic description of parameter variations of the design is formulated. Stochastic quantities are computed by Monte Carlo sampling to rate the robustness. A...

Improved Representation of High Lift Devices for a Multidisciplinary Preliminary Aircraft Design Process

A methodology for improving the quality of high-lift-system performance prediction within a multidisciplinary conceptual design process is presented. The high-lift-system geometry is explicitly modeled and a multiple-lifting-line method is used to compute its aerodynamic characteristics. Computation times are acceptable for use in a conceptual design process. The results for several test cases show good agreement with wind-tunnel and/or high-fidelity numerical data. In addition, the method allows for further enhancement by using nonlinear airfoil polars for interpolation, improving drag prediction, and introducing some degree of nonlinear aerodynamic behavior.

Assessment of the Noise Immission along Approach and Departure Flightpaths for Different SFB 880 Vehicle Concepts

The number of flight movements is further increasing in the future and some major airports are already at their capacity limit. Therefore, it becomes beneficial for short range aircraft to operate on regional airports as well. Short range aircraft with conventional high-lift systems, however, are not able to safely operate on the comparatively short runways of regional airports. Instead, new aircraft concepts are required that are equipped with an active high-lift system. Such an active high-lift system offers high lift coefficients and thus the ability for short take-off and landing. In order to ensure a sustainable growth in aviation, such new aircraft concepts also have to offer reduced fuel consumption and low noise on the ground. The Coordinated Research Center (SFB) 880 focuses on such an active high-lift system. This active high-lift system is comprised of a flexible leading edge device, referred to as Droop nose, and an internally blown flap at the trailing edge, referred to as Coanda flap. Within the SFB880, the active high-lift system is applied to several aircraft concepts. These aircraft concepts are equipped with different propulsion systems, that is, turbofan engines of different bypass ratio or a turbine-driven propeller engine. In this study, the noise prediction methodology for the noise assessment within the SFB880 is summarized and applied to the aircraft concepts. The assessment includes the noise at the three noise certification points as well as along a line of observers. The study also includes a preliminary uncertainty assessment in order to evaluate the reliability of the predicted noise on the ground. The results show that the SFB vehicles can provide significant noise reduction compared to a reference aircraft with a conventional high-lift system and turbofan engine. Most noise reduction can be achieved with the aircraft that is equipped with the ultra-high bypass ratio turbofan engine.

An Optimal Configuration of an Aircraft with High Lift Configuration Using Surrogate Models and Optimisation Under Uncertainties

Nowadays many simulations are computationally expensive, which is disadvantageous if one is interested in the quantification of uncertainties, parameter studies or in finding an optimal or robust design. Therefore often so-called surrogate models are designed, which are a good approximation of the original model but computationally less expensive.