The company OPTIMENGA provides a unique software based solution OPTIMENGA_AERO for aerodynamic design and analysis and consulting services in this field.
The code OPTIMENGA_AERO is a new robust and efficient tool for design and analysis of aerodynamic wings in a wide range of flight conditions.
The design aims at finding optimal aerodynamic shape with as low a drag of the air vehicle (at given lift) as possible while satisfying numerous constraints placed upon its geometry and aerodynamic characteristics. In solving the problem of multi-point optimization, the algorithm employs hybrid genetic search for optimal shapes. For fitness evaluation, a combination of a Reduced-Order-Models method with high accuracy Navier-Stokes solutions is employed through the construction of interconnected local databases.
The uniqueness and high efficiency of OPTIMENGA_AERO is determined by the following features:
- A novel strategy for handling non-linear constraints placed upon the optimal solution which allows to satisfy up to 100 constraints imposed on wing shape and aerodynamic characteristics
- High accuracy numerical solver for the full Navier-Stokes equations used for design and analysis
- Efficient multi-level strategy of parallel computations on multiprocessor clusters,
- Overall high level of computational efficiency and robustness which allows for optimal shape design in the shortest time possible
Numerical solution of Navier-Stokes equations is computed by means of OPTIMENGA_NASTIA software. The solver employs multi-block numerical grids and a higher-order approximation scheme. OPTIMENGA_NASTIA allows for high accuracy of Navier-Stokes solutions on relatively coarse grids and ensures a high level of robustness in a wide range of free-stream Mach and Reynolds numbers and wing geometries.
The software OPTIMENGA_AERO which includes the latest developments in Computational Fluid Dynamics alongside novel optimization techniques, can be successfully used for practical aerodynamic design and analysis. On a standard computer cluster, an optimization of three-dimensional wing typically takes about 15-16 hours.
The system operates in a fully automated regime. The input parameters to OPTIMENGA_AERO are wing planform, starting sectional airfoils and design (or analysis) points. A user-friendly GUI ensures that the tool can be used by aerodynamic engineers irrespective of their knowledge in the field of numerical methods or optimization. Another important advantage of the tool is that all numerical grids required for design and analysis, are built automatically without any intervention of the user.
The optimization target is the total wing drag at fixed aerodynamic design conditions (lift coefficient, free stream Mach and Reynolds numbers). The wing planform is kept fixed while wing section airfoils, twist and dihedral values are subject to change.
The code also performs multipoint optimization which minimizes a weighted combination of drag values at specified design points (e.g. at cruise and take-off conditions)
An additional operational mode of OPTIMENGA_AERO is the analysis mode. In this mode, the system performs accurate flow analysis based on numerical solution of full Navier-Stokes equations in prescribed flight conditions.
Though the flow analysis (used in both optimization and analysis modes) employs numerical grids for solving the flow equations, no grid generation is required from the user.
OPTIMENGA_AERO makes use of the built-in basic grid, which is automatically adjusted to the changing geometry, and thus the grid generation process is transparent to the user. OPTIMENGA_AERO operates under Operating System LINUX and PVM (Parallel Virtual Machine) on standard parallel clusters.
Overall, the software allows for significant improvement in aerodynamic characteristics of the wing at specified design points, ensures good aerodynamic characteristics in a wide range of flight conditions and significantly reduces the design cost both in terms time and money.
This enables to switch from the traditional trial-and-error aerodynamic design process (based on the aerodynamic intuition and engineering experience of at least 2-3 experienced aerodynamic designers) to an automated design driven by OPTIMENGA_AERO. As a result, the time required for one design cycle can be reduced to 1-2 weeks (compared with 2-3 months with the traditional approach), and the design can be performed by a designer with moderate experience.
OPTIMENGA_AERO was successfully tested in industry. An intensive verification of this design tool demonstrated that it has an edge over existing counterparts in terms accuracy and robustness.
Fig.1 Pressure distribution on the upper surface of the initial wing (left, CD = 359.0 counts, strong shock wave) and the optimal wing designed by OPTIMENGA_AERO (right, CD = 266.0 counts, the shock wave practically eliminated). The design conditions: M=0.75, CL=0.70.