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Papers by Andreas Krumbein
Aerospace Science and Technology, Dec 1, 2008
Notes on numerical fluid mechanics and multidisciplinary design, 2010
Journal of Aircraft, Sep 1, 2005
Journal of Aircraft, 2007
ABSTRACT A Reynolds-averaged Navier-Stokes solver, a laminar boundary-layer code and different tr... more ABSTRACT 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 flow computation. In this article, the procedure is applied to a two-dimensional three-element high-lift airfoil configuration which is characterized by the existence of laminar separation bubbles. The automatic transition prediction procedure is applied using different operation modes and different transition prediction strategies.
This report has been made during the European project HiAer - High Level Modeling of High Lift Ae... more This report has been made during the European project HiAer - High Level Modeling of High Lift Aerodynamics. Within the project, the report was published as deliverable D1.1-1. The report consists of two parts. The first part, Navier-Stokes Airfoil Computations with e* Transition Prediction Including Transitional Flow Regions, contains the theoretical background for the work done in Task 1.1, that is dedicated to the implementation of new infrastructure into the flow solvers. The second one, Modeling of Transitional Flow and its Application on a High Lift Multi-element Airfoil Configuration, describes the implementation of the theory into a Navier-Stokes code and its applications and contains test case results. The flow around laminar airfoils can be computed using a Navier-Stokes method coupled to a transition prediction method based on the e* approach. Applying point transition at the predicted transition location produces a strong viscous/inviscid interaction region which prevents the coupled system to converge, whereas the introduction of transitional flow regions resolves that problem. A conventional model is proposed, which is applicable in flow regions where transition is predicted well upstream of laminar separation, together with a special transitional length model for flows where the boundary-layer stays laminar up to separation. The implementation of the model into a Navier-Stokes code is described and the strategy of determing the transition locations is outlined. The model is tested at a 2-dimensional high lift configuration consisting of the three elements. Computational results for two different versions of the transitional length are shown and compared. The second part of the report focuses on the background of the implementation work and the testing of the functionalities of the algorithms. Details of the implementation, which are consequences of the transition prediction strategy, are outlined. The testing is described and documented by a large number of commented plots of the computed flow fields and the results of the approximate transition prediction procedure and the transition length models. The main objective of this task is to supply a reliably working infrastructure in a RANS code to perform the desired approximate transition prediction. This report is documenting that the work has successfully been done.
Notes on numerical fluid mechanics and multidisciplinary design, 2009
Springer eBooks, Oct 1, 2006
AIAA SCITECH 2022 Forum, Jan 3, 2022
Springer eBooks, Oct 17, 2007
Notes on numerical fluid mechanics and multidisciplinary design, 2006
Springer eBooks, 2002
This paper presents the strategy and application of the coupling of a Navier-Stokes solver with a... more This paper presents the strategy and application of the coupling of a Navier-Stokes solver with a transition prediction method. For industrial applications the coupling of the solver to an database method, based on local linear stability theory, results in a program system that is able to automatically handle transition prediction. The solver was coupled to a transition prediction module, consisting of a boundary layer method for swept, tapered wings and engineering transition prediction methods, a.) two algebraic, empirical transition criteria and b.) an eN-database method for Tollmien-Schlichting waves. The sensitivity of the coupled system with regard to a change of system parameters was investigated. It could be shown that for some of the parameters the sensitivity does not exist and that it is very low for the others.
Journal of Aircraft, Sep 1, 2013
ABSTRACT The correlation-based gamma-Rethetat transition transport model was implemented into a h... more ABSTRACT The correlation-based gamma-Rethetat transition transport model was implemented into a hybrid Reynolds-Averaged Navier-Stokes solver and validated on various test cases. The gamma-Rethetat model predicts two-dimensional transition phenomena such as transition due to Tollmien-Schlichting instabilities and separation-induced transition. The present work includes results for the application of the gamma-Rethetat model to two three-dimensional test cases, which are the 6:1 inclined prolate spheroid and the ONERA M6 wing. Depending on the flow conditions, the computational results are in good agreement with the experimental data. Once, the given flow conditions lead to three-dimensional transition phenomena, the transition prediction with the gamma-Rethetat model is not reliable, because the model is based on the characteristics of two-dimensional boundary layers and three-dimensional transition mechanisms are not taken into account. In order to close this gap, the gamma-Rethetat model was extended by an approach which accounts for transition due to crossflow-instabilities in three-dimensional boundary layers. This approach and its implementation into the original model are introduced in this paper. First results for the flow over two different infinite swept wing configurations which are the ONERA D wing and the NLF(2)-0415 wing are presented.
Journal of Aircraft, Jul 1, 2018
Two crossflow transition prediction approaches, the local C1-based approach and the local helicit... more Two crossflow transition prediction approaches, the local C1-based approach and the local helicity-based approach, have been implemented into a Reynolds-stress-based transition transport model of t...
ABSTRACT A Reynolds-averaged Navier-Stokes solver, a laminar boundary-layer code and different tr... more ABSTRACT 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 flow computation. In this article, the procedure is applied to a two-dimensional three-element high-lift airfoil configuration which is characterized by the existence of laminar separation bubbles. The automatic transition prediction procedure is applied using different operation modes and different transition prediction strategies.
AIAA Journal, Jul 1, 2022
Aerospace Science and Technology, Dec 1, 2008
Notes on numerical fluid mechanics and multidisciplinary design, 2010
Journal of Aircraft, Sep 1, 2005
Journal of Aircraft, 2007
ABSTRACT A Reynolds-averaged Navier-Stokes solver, a laminar boundary-layer code and different tr... more ABSTRACT 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 flow computation. In this article, the procedure is applied to a two-dimensional three-element high-lift airfoil configuration which is characterized by the existence of laminar separation bubbles. The automatic transition prediction procedure is applied using different operation modes and different transition prediction strategies.
This report has been made during the European project HiAer - High Level Modeling of High Lift Ae... more This report has been made during the European project HiAer - High Level Modeling of High Lift Aerodynamics. Within the project, the report was published as deliverable D1.1-1. The report consists of two parts. The first part, Navier-Stokes Airfoil Computations with e* Transition Prediction Including Transitional Flow Regions, contains the theoretical background for the work done in Task 1.1, that is dedicated to the implementation of new infrastructure into the flow solvers. The second one, Modeling of Transitional Flow and its Application on a High Lift Multi-element Airfoil Configuration, describes the implementation of the theory into a Navier-Stokes code and its applications and contains test case results. The flow around laminar airfoils can be computed using a Navier-Stokes method coupled to a transition prediction method based on the e* approach. Applying point transition at the predicted transition location produces a strong viscous/inviscid interaction region which prevents the coupled system to converge, whereas the introduction of transitional flow regions resolves that problem. A conventional model is proposed, which is applicable in flow regions where transition is predicted well upstream of laminar separation, together with a special transitional length model for flows where the boundary-layer stays laminar up to separation. The implementation of the model into a Navier-Stokes code is described and the strategy of determing the transition locations is outlined. The model is tested at a 2-dimensional high lift configuration consisting of the three elements. Computational results for two different versions of the transitional length are shown and compared. The second part of the report focuses on the background of the implementation work and the testing of the functionalities of the algorithms. Details of the implementation, which are consequences of the transition prediction strategy, are outlined. The testing is described and documented by a large number of commented plots of the computed flow fields and the results of the approximate transition prediction procedure and the transition length models. The main objective of this task is to supply a reliably working infrastructure in a RANS code to perform the desired approximate transition prediction. This report is documenting that the work has successfully been done.
Notes on numerical fluid mechanics and multidisciplinary design, 2009
Springer eBooks, Oct 1, 2006
AIAA SCITECH 2022 Forum, Jan 3, 2022
Springer eBooks, Oct 17, 2007
Notes on numerical fluid mechanics and multidisciplinary design, 2006
Springer eBooks, 2002
This paper presents the strategy and application of the coupling of a Navier-Stokes solver with a... more This paper presents the strategy and application of the coupling of a Navier-Stokes solver with a transition prediction method. For industrial applications the coupling of the solver to an database method, based on local linear stability theory, results in a program system that is able to automatically handle transition prediction. The solver was coupled to a transition prediction module, consisting of a boundary layer method for swept, tapered wings and engineering transition prediction methods, a.) two algebraic, empirical transition criteria and b.) an eN-database method for Tollmien-Schlichting waves. The sensitivity of the coupled system with regard to a change of system parameters was investigated. It could be shown that for some of the parameters the sensitivity does not exist and that it is very low for the others.
Journal of Aircraft, Sep 1, 2013
ABSTRACT The correlation-based gamma-Rethetat transition transport model was implemented into a h... more ABSTRACT The correlation-based gamma-Rethetat transition transport model was implemented into a hybrid Reynolds-Averaged Navier-Stokes solver and validated on various test cases. The gamma-Rethetat model predicts two-dimensional transition phenomena such as transition due to Tollmien-Schlichting instabilities and separation-induced transition. The present work includes results for the application of the gamma-Rethetat model to two three-dimensional test cases, which are the 6:1 inclined prolate spheroid and the ONERA M6 wing. Depending on the flow conditions, the computational results are in good agreement with the experimental data. Once, the given flow conditions lead to three-dimensional transition phenomena, the transition prediction with the gamma-Rethetat model is not reliable, because the model is based on the characteristics of two-dimensional boundary layers and three-dimensional transition mechanisms are not taken into account. In order to close this gap, the gamma-Rethetat model was extended by an approach which accounts for transition due to crossflow-instabilities in three-dimensional boundary layers. This approach and its implementation into the original model are introduced in this paper. First results for the flow over two different infinite swept wing configurations which are the ONERA D wing and the NLF(2)-0415 wing are presented.
Journal of Aircraft, Jul 1, 2018
Two crossflow transition prediction approaches, the local C1-based approach and the local helicit... more Two crossflow transition prediction approaches, the local C1-based approach and the local helicity-based approach, have been implemented into a Reynolds-stress-based transition transport model of t...
ABSTRACT A Reynolds-averaged Navier-Stokes solver, a laminar boundary-layer code and different tr... more ABSTRACT 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 flow computation. In this article, the procedure is applied to a two-dimensional three-element high-lift airfoil configuration which is characterized by the existence of laminar separation bubbles. The automatic transition prediction procedure is applied using different operation modes and different transition prediction strategies.
AIAA Journal, Jul 1, 2022