Transition Prediction and Modeling in External Flows Using RANS-based CFD Codes

Darstellung der Arbeiten und des Entwicklungs- und Anwendungsstandes der Transitionsmodellierung und Transitionsvorhersage in den DLR RANS-Lösern TAU und FLOWer (mit Fokus auf den DLR TAU-Code) in Form eines Übersichtsvortrage

Determination of Critical N-Factors for the CRM-NLF Wing

Temperature sensitive paint images from a wind tunnel campaign for the CRM-NLF geometry are used to extract experimental transition lines to be used to determine critical N-factors based on incompressible and compressible linearstability theory. Based on the eN-method, transition locations are subsequently predicted for different flow conditions using RANS computations and the results are compared to the experiment

Automatic Transition Prediction for Three-Dimensional Configurations with Focus on Industrial Application

A computational method to predict transition lines for general three dimensional configurations is presented. The method consists of a coupled program system including a 3D Navier-Stokes solver, a transition prediction module, a boundary-layer code and a stability code. Focus is placed on the industrialization of the approach. For this, the transition prediction module has been adapted to be used for parallel computation to account for high computational demands for three dimensional configurations. Different calculation methods for the laminar boundary layer that are available in the transiton prediction module are presented. The method is validated against experimental data of the flow around an inclined prolate spheroid. Application examples are shown for different three-dimensional aircraft configurations and topics arising from these tests concerning the industrialization of the method are discussed

Navier-Stokes High-Lift Airfoil Computations with Automatic Transition Prediction using the DLR TAU Code

A Reynolds-averaged Navier-Stokes solver, a laminar boundary-layer code and different transition prediction methods for the prediction of Tollmien-Schlichting and cross flow instabilities were coupled for the automatic prediction of laminar-turbulent transition on general 3-dimensional aircraft configurations during the ongoing computation of the flow. The prediction procedure is applied to a two-dimensional three-element high-lift airfoil configuration which is characterized by the existence of laminar separation bubbles using different operation modes of the procedure

Automatic Transition Prediction with the eN-Method for Three-Dimensional, Industrially Relevant Configurations

A computational method to predict transition for three-dimensional configurations is presented. The method consists of a coupled program system including a 3D Navier-Stokes solver, a transition prediction module, a boundary-layer code and a stability code. Approaches to treat different, complex three-dimensional aircraft geometries and to account for limitations of the transition prediction method in an industrial computational environment are presented