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|LINFLOW Brochure Download|
LINFLOW has been developed to bridge the gap between fluid dynamics and structure dynamics to give the engineer an efficient tool to learn and understand the characteristics of the dynamics of the fully coupled system of fluid and interfacing structure. Also, LINFLOW makes it possible to study the response of aero- and fluid-elastic systems within a very reasonable timeframe. We have seen computer time several orders of magnitude lower than with other concepts; the results computed in LINFLOW comparing extremely well with measurements.
Because of the general and the rigorous mathematical and numerical concepts behind LINFLOW, users can study internal and external acoustics accounting for steady flow effects ("acoustics in flowing media").
LINFLOW is based on the Boundary Element Method for the discretization of the velocity potential, and is entirely a development of ANKER - ZEMER Engineering AB in Karlskoga, Sweden.
LINFLOW covers Fluid Flow, Aeroelasticity, Acoustics, Fluid-Structure Interaction, and Aeroelastic Stability. Aeroelastic Stability analysis is what one would perform to see if there is a chance that flutter will occur considering the system at hand.
LINFLOW is an excellent tool for the study of Propellers, Fans, Vibrations in Ducts and Pipes due to internal Fluid Flow, Lift and Drag of Airfoils and Spoilers, Acoustics, and general FSI.
The Current Release of LINFLOW is Rel. 1.4, released in December 2004. New is a Spectrum Analysis (PSD) Module, Enhanced p-k-Stability Analysis Module, a (Semi-) Automatic Wake Element Generation Tool, and Improved Numerical Procedures. There are also other enhancements introduced.
The concepts introduced with LINFLOW are very different from other concepts for fluid structure interaction - FSI. A concept for simulating FSI phenomena utilized by many software vendors is to couple Navier-Stokes Solvers for general fluid flow with Finite Element based software for statics and structural dynamics. The concept of a "direct coupling" between CFD and Structural Analysis is very general and will work well for certain classes of problems.
The advantage of the direct coupling is that it allows for the inclusion of structural nonlinear effects in the coupled problem. The disadvantage of the direct coupling is that it is not very well suited for vibration problems (e.g. acoustics, aeroelasic stability analysis for the prediction of flutter). Even for a single point solution of small, low frequency problems, the approach is computationally very inefficient, requiring substantial computational resources. For higher and high frequency problems (e.g. fans, flow induced vibrations in pipes) the concept based on a direct coupling between a Navier-Stokes solver and a structural analysis program is practically infeasible due to the computer resources needed. Small amplitude, high frequency FSI-problems will be solved several orders of magnitude faster with LINFLOW than with software based on other concepts.
LINFLOW can be used for the study of fluid flow, given that the fluid can be considered inviscid and irrotational. However, there are many FSI problems where a Navier-Stokes Solver is needed to capture the fluctuations in the flow-field due to viscous effects as input to a LINFLOW based simulation; in this case, the calculated spectrum of the unsteady pressure oscillation will be used as loading in subsequent LINFLOW aero-/fluid-elastic response analysis (example here).
|Compressible incompressible fluid flow.||Acoustics analysis with LINFLOW.|
|Turbulent flow structures around landing gear .||Squeezed film effects in MEMS.|
|LINFLOW Presentation Download|
|An Interpretation of the physics of Fluid-Structure Interaction in the frequency domain Download|
|Fluid-structure interaction model for a vibrating cantilever Download|