Robert Roszak

Genetic Algorithm-based Calibration of Reduced Order Galerkin Models

Abstract Low-dimensional models, allowing quick prediction of fluid behaviour, are key enablers of closed-loop flow control. Reduction of the models dimension and inconsistency of high-fidelity data set and the reduced-order formulation lead to the decrease of accuracy. The quality of Reduced-Order Models might be improved by a calibration procedure. It leads to global optimization problem which consist in minimizing objective function like the prediction error of the model. In this paper, Reduced-Order Models of an incompressible flow around a bluff body are constructed, basing on Galerkin Projection of governing equations onto a space spanned by the most dominant eigenmodes of the Proper Orthogonal Decomposition (POD). Calibration of such models is done by adding to Galerkin System some linear and quadratic terms, which coefficients are estimated using Genetic Algorithm.

Continuous Mode Interpolation between Multiple Operating and Boundary Conditions for Reduced Order Modelling of the Flow

Galerkin Projection is one of the most popular methods of flow model’s reduction. Mode basis used in Galerkin expansion allows reconstruction of the flow for a given set boundary and operating conditions. In the case of changing flow conditions, used mode basis has to be adjusted, for example using mode parametrization [1] or Continuous Mode Interpolation [2]. In this paper an expansion of interpolation technique, allowing a smooth transition between multiple flow states, is presented. Applications include the flow around circular cylinder and a NACA airfoil. The resulting state‐dependent Galerkin expansion addresses the need of robust control‐oriented models for sufficiently broad dynamic range in a low dimensional phase‐space.

Deformation of Curvilinear Meshes for Aeroelastic Analysis

The article presents elastic analogy approach of deformation curvilinear meshes applied in aeroelastic simulations. The details of algorithm used in developed software with the new metrics designated for high-order mesh quality assessment are presented. The article ends the example of LANN wing deformed by featured tool. Presented software allows conducting the aeroelastic simulation based on CFD discontinuous Galerkin High Order solver.

Aeroelastic Testcases in IDIHOM Project

In the IDIHOM Project three aeroelastic testcases have been calculated. Two of them - LANN Wing and DLR-F6 wing-body configuration - have been conducted by PUT. The last one, the HART II rotor has been prepared by NLR. Each partner has used different technology and software tools, hence each of the testcases describes the results of the simulation and technology which has been used.

Fluid Structure Interaction for Symmetric Manoeuvre Base on Ultra Light Plane

Expansion of computer technology enables use of computer simulation for prediction of aircraft characteristics in early stages of design. These simulation nowadays include highly sophisticated and reliable aerodynamics computations as well as solutions of coupled aeroelastic interactions. In this paper we consider numerical simulation of the full‐configuration ultra‐light aircraft manoeuvre. The simulation takes into account the aeroelastic effects. Simulation is performed for the I23 aircraft. For this configuration the flight test data is aviable. The data include plane behavior during the manoeuver. The aeroelastic system used in this simulation consists of structural and fluid part coupled via coupling surface. The structural model of I23 is simulated with the modal approach, using 24 normal modes. This number includes four rigid modes necessary for the manouver simulation. CFD part of the aeroelastic system comprise DLR TAU‐code. In addition, the interpolation tools as well as mesh deformation are in...

The Numerical Analysis of Influence of Crankshaft Main Spindles Regeneration in Marine Engine on Stiffness and Eigenfrequency of the Crankshaft

Engine operating conditions of the main propulsion, static in principle with steady-state rotation speed of the crankshaft and engine load, also work under dynamic load conditions. These conditions cause additional distortion of the crankshaft and changes in the operating conditions of the shaft bearings. However, the greatest impact on the long and trouble-free operation has proper engine maintenance. Variable operating conditions and engine operating errors, unfortunately, often cause damage to the main bearings of the crankshaft. Repair of the damaged main bearing spindles of the shaft involves performing the machining of the spindle surface then its re-hardening and selecting new bearing bushings with the appropriate bearing clearance. Trusting the engine manufacturer, there is no check of the influence of the machining of bearing spindles on the structural properties of the shaft. Therefore, the paper presents the model tests of the structure of medium-rev marine engine crankshaft aimed at determining the changes in the mechanical properties of the structure resulting from carrying out the regeneration of the main shaft spindles.

Aeroelastic System for Large Scale Computations with High Order Discontinuous Galerkin Flow Solver

Article presents the development process of aeroelastic system basing on finite volume CFD solver for higher order methods. The main aspect is interpolation tools which allows application of Discontinuous Galerkin solution of CFD solver. There is also described the elastic analogy deformation tool for curvilinear mesh. To summarize, the two testcases of wing and wing-body configuration aircraft are presented.