applications


HyperWorks 2017 demonstrates Altair’s capabilities in FE pre- and post-processing


As a result, components are rarely


modelled in isolation and only in cases of very high fidelity where a particularly complex non-linear behaviour is being simulated. Johns explained: ‘Te sheer complexity of the problem under consideration limits the scale to a single component. Complex engineering products are designed for a system level optimum. Over-optimisation of a single component can cause the overall system to become sub-optimal.’


Multi-scale Te aerospace industry has developed very reliable methods to simulate across scales and incorporate the components making up a vehicle. Tis helps the sector strike the right


possibly, even acoustics as noise is becoming more important from the passenger and environmental noise perspective.’ Te entire propulsion system and its


components are also heavily simulated. Te components in the engine operate in the harshest environment – some even operate at temperatures above melting point that without continuous cooling would not last very long. Harwood added: ‘Simulation is the only


cost-effective way to ensure these components can survive the environment they will operate in, before they are tested in very expensive experiments. And these simulations span the entire range of physics, from aerodynamics, structural mechanics, impact, thermal, and so on.’ Electromagnetic modelling is also done


for all of the electronic systems, antennas, wireless, sensors, and cabling inside today’s aerospace systems. Yancey said: ‘With the increasing use of electronics in modern aerospace systems, these tools are being used more widely for increasingly complex electronic systems designs.’


Bringing it together Te simulation and modelling of all of these components is no mean feat – and not always necessary, depending on the simulation scenario. For example, integrated aerodynamic quantities, such as liſt and drag, can be accurately predicted within


www.scientific-computing.com l @scwmagazine


FINDING THE SOURCES OF ADDITIONAL


IMPROVEMENT IS VERY, VERY DIFFICULT AND SIMULATION IS A KEY TECHNIQUE TO RAPIDLY AND COST-EFFECTIVELY EXPLORE NEW IDEAS


a certain design range without including the smallest components of a system, according to Dr Cetin Kiris, computational aerosciences branch chief at the NASA Advanced Supercomputing (NAS) Division, who added: ‘But, there are many cases where including full fidelity (geometry and physics) is required to capture more complex phenomena, such as acoustic noise during take-off and landing.’ Te main trade-off for such decisions is


between the cost of prototype manufacture and testing, versus the cost of component modelling and simulation, according to Guy Johns, lead technologist at the Centre for Modelling and Simulation (CFMS), who added: ‘Modelling and simulation can be more cost-effective, however, it has a higher uncertainty associated with the results and, typically, a more limited dataset compared with real world test rigs.’


balance between the required level of detail to model and simulating for the objective to be met. For example, reduced order modelling (ROM) allows the complexity of a high fidelity case (or real-world dataset) to be reduced. Multi-physics simulation tools and


mixed fidelity modelling also exist, as Kiris explained: ‘Resolving a range of time and space scales is critical to accurately simulating an entire aerospace vehicle. For example, wall boundary layers contain scales that can be many orders of magnitude smaller than the vehicle surfaces which determine them. ‘To handle this, computational fluid


mechanics experts utilise multi-scale methods, packing fine mesh resolution only where it is required, such as on smaller components or across flow features such as boundary layers, and utilise coarser discretisations elsewhere,’ he added. Valerio Marra, marketing director at


COMSOL, said: ‘When a multiphysics approach is adopted, a high-fidelity model can be built that reflects reality closely and serves as an accurate predictor of a design’s performance by including all of the physical phenomena involved and being able to describe the interactions as they happen in the real world.’ Tat said, optimising an entire aircraſt


system on a single execution is still too big a challenge for the simulation and modelling sector. However, there are means to exchange information through surrogate modelling, which allows multi-fidelity models to use the right fidelity at the right time during the design process. Carlo Poloni, CEO at


APRIL/MAY 2017 27


➤


Altair


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36