Comparison of two- and three-dimensional Navier-Stokes solutions with NASA experimental data for CAST-10 airfoil

The two-dimensional (2-D) and three-dimensional Navier-Stokes equations are solved for flow over a NAE CAST-10 airfoil model. Recently developed finite-volume codes that apply a multistage time stepping scheme in conjunction with steady state acceleration techniques are used to solve the equations. Two-dimensional results are shown for flow conditions uncorrected and corrected for wind tunnel wall interference effects. Predicted surface pressures from 3-D simulations are compared with those from 2-D calculations. The focus of the 3-D computations is the influence of the sidewall boundary layers. Topological features of the 3-D flow fields are indicated. Lift and drag results are compared with experimental measurements

Technical Evaluation Report for Symposium AVT-147: Computational Uncertainty in Military Vehicle Design

The complexity of modern military systems, as well as the cost and difficulty associated with experimentally verifying system and subsystem design makes the use of high-fidelity based simulation a future alternative for design and development. The predictive ability of such simulations such as computational fluid dynamics (CFD) and computational structural mechanics (CSM) have matured significantly. However, for numerical simulations to be used with confidence in design and development, quantitative measures of uncertainty must be available. The AVT 147 Symposium has been established to compile state-of-the art methods of assessing computational uncertainty, to identify future research and development needs associated with these methods, and to present examples of how these needs are being addressed and how the methods are being applied. Papers were solicited that address uncertainty estimation associated with high fidelity, physics-based simulations. The solicitation included papers that identify sources of error and uncertainty in numerical simulation from either the industry perspective or from the disciplinary or cross-disciplinary research perspective. Examples of the industry perspective were to include how computational uncertainty methods are used to reduce system risk in various stages of design or development

PhDCube – Initiative der NTH zur Förderung der Promotion in den Grundlagen des Ingenieurwesens

Die drei Mitgliedsuniversitäten der Niedersächsischen Technischen Hochschule NTH haben sich auf eine gemeinsame und strategisch angelegte Initiative zur Förderung des wissenschaftlichen Nachwuchses in den Grundlagen des Ingenieurwesens verständigt. Diese Initiative für eine Standort übergreifende Graduiertenschule in der NTH beruht auf Konzepten für die wissenschaftliche Ausrichtung, für die strukturierte Ausbildung von Doktoranden in der NTH und für die Vernetzung innerhalb der NTH und mit externen Kooperationspartnern

Neue Hochauftriebssysteme für zukünftige Verkehrsflugzeuge

International audienc

Grey area in Embedded WMLES on a transonic nacelle-aircraft configuration

A scale resolving hybrid RANS-LES technique is applied to an aircraft-nacelle configuration under transonic flow conditions using the unstructured, compressible TAU solver. Therefore, a wall modelled LES methodology is locally applied to the nacelle lower surface in order to examine shock induced separation. In this context a synthetic turbulence generator (STG) is used to shorten the adaption region at the RANS-LES interface. Prior to the actual examinations, fundamental features of the simulation technique are validated by simulations of decaying isotropic turbulence as well as a flat plate flow. For the aircraft-nacelle configuration at a Reynolds number of 3.3 million a sophisticated mesh with 420 million points was designed which refines 32 % of the outer casing surface of the nacelle. The results show a development of a well resolved turbulent boundary layer with a broad spectrum of turbulent scales which demonstrates the applicability of the mesh and method for aircraft configurations. Furthermore, the necessity of a low dissipation low dispersion scheme is demonstrated. However, the distinct adaption region downstream of the STG limits the employment of the method in case of shock buffet for the given flow conditions

Extending the turbulent length scale equation with the use of LES data

The k − kL closure model naturally occurring higher derivative terms, and due to its nature provides a good starting point for studying effects of inflectional instabilities in wakes. In this work, results of scale resolving simulations of a turbulent boundary layer and its corresponding wake at adverse pressure gradients are evaluated with the aim of establishing physics based bounds and assumptions for the expansion of turbulent length scale equations to improve RANS predictive capability for adverse pressure gradients