SIMULIA XFlow CFD

Compute aerodynamic loads over complex geometry, including rotating wheels and moving parts. Analyze overtaking or dynamic systems like vehicle suspension through co-simulation with external Multi-Body Dynamic (MBD) software. The virtual wind tunnel module includes a moving ground option and enables users to setup simulations in record time.

Use XFlow CFD for reduction of aerodynamic noise levels in and around vehicles like HVAC Systems, sideview mirrors and open windows effects. Xflow computes pressure wave propagation instead of modeling the radiation propagation of such waves. Including many acoustics post-processing features such as FFT, PSD, SPL, windowing, signal filtering and band-pass filter pressure field visualization which allow a full acoustic analysis to be performed inside XFlow.

The Free-surface solver of XFlow CFD allows water management analysis to be performed, such as flow inside the rain chamber, refueling process, tank sloshing or a drive through of a complete vehicle with real rotating wheels. The adaptive refinement of XFlow dynamically refines water splashing areas while saving elements on other more stable regions, reducing overall simulation time.

Under hood aerodynamic flows or internal air circulation inside the car cabin can be easily simulated using XFlow CFD through a straightforward workflow. The particle-based approach avoids the time-consuming traditional meshing process. Moreover, the particle-based method of XFlow allows under hood analysis with many complex, arbitrary moving geometries and porous media to be performed, skipping the long meshing process usually required to prepare such simulations.

XFlow is used by leading powertrain manufacturers for lubrication applications, mass flow distribution through rotating shafts and gear torque prediction. XFlow CFD uses multiphase solvers that accurately solve the interaction between any two immiscible fluids and easily handles perfect contacts between real unsimplified moving gears without any specific preliminary preparation.

Vehicle internal heating, ventilation or air conditioning are simulated through the thermal capabilities integrated in XFlow CFD. These capabilities allow both thermal convection in the fluid and thermal conduction inside solids (Conjugate Heat Transfer) to be solved, which are very well suited for engine cooling analysis applications.

XFlow CFD is used to simulate real rotating fans or alternatively model them using a simplified fan boundary condition. Agitators and mixers for the chemical industry, water treatment plants or even domestic devices are easily simulated. It solves single and two-phase flows for immiscible fluids including surface tension. Scalar transport models are available and can be used to track the fluids mixing evolution.

Fluid atomization and spray droplets are simulated using the free-surface or multiphase solver in XFlow and tracked dynamically with the adaptive refinement feature which dynamically and locally refines the regions where the droplets are splashing. Such a capability makes some automotive applications possible by CFD such as windshield washer nozzles or carbody spraypaint.

XFlow CFD easily handles moving parts with Enforced and Rigid Body Dynamics behavior which is suitable for Valve applications where it is very important to simulate the valve dynamics. It is also possible to specify a law to model the spring force applied on the valve. XFlow has already demonstrated its accuracy in predicting the pressure drop as a function of the flow inside the valves as well as the vibrations and instabilities of valves. Centrifugal or displacement pumps are set up and simulated very easily, not only for isolated operational points but also for full cycles or accidental events in which the engineer wants to analyze in detail the transient dynamics of the system.

The thermal fluid applications can be solved with XFlow thanks to the different thermal solvers available in the code. It allows thermal analysis together with aerodynamic analysis to be performed, which is very important for cooling/heating problems. The Conjugate Heat Transfer model allows the conduction inside solids to be solved and simulates, for example, how a hot external flow affects the internal temperature distribution inside a solid. For manufacturing applications where electronics components are placed close to heat sources, the radiation contribution is very important. XFlow provides a surface-to-surface radiation model where the emissivity coefficient of each surface can be specified in order to solve the contribution of each surface in the global thermal analysis.

State-of the-art multiphase solvers are implemented in XFlow in order to enable the user to solve the interaction between two fluids at different scales with different density and viscosity ratios, for inertial or viscous dominant applications. These multiphase solvers give the possibility to simulate a wide range of manufacturing applications such as bubbles creation, fluids mixing, lubrication and fluid atomization.

Highly viscous non-Newtonian fluids (e.g. melted plastic, molding, chemical blends, toothpaste) are common in many industrial applications. The complex rheological properties of these fluids can be introduced in XFlow CFD by using the predefined viscosity models available (Newtonian, Sutherland, Cross, Herschel-Bulkley, Power Law, Carreau) or user-defined functions.

XFlow provides a virtual water channel module for free surface simulations. It can be used to analyze the flow around ship hulls, predict their resistance, seakeeping, loads on components, and the downstream wake of both surface and submerged watercraft.
The adaptive refinement algorithm of XFlow can also detect and refine dynamically and automatically the ship wake and the free-surface of the fluid. For sailing boats, the multiphase solvers of XFlow allows both hydrodynamic analysis on the boat and aerodynamic analysis on the sail to be performed at the same time.

XFlow can be used to simulate moving parts rigid dynamics behavior, such as boat dynamics with six degrees of freedom, this feature allows the effect of the change of the heave on the roll or yaw angle of the boat or the effect of an increasing inlet flow on the roll angle of the boat to be analyzed dynamically. XFlow is also well suited to simulate moving parts with enforced behavior such as to carry out boat maneuvers simulations or carrier ships simulations with real rotating propellers or modeled ones.

The solver supports progressive waves boundary conditions by implementing linear and fifth order Stokes theory to simulate a wide range of sea conditions. This is suitable for studying seakeeping of boat hulls, for predicting floating buoy behaviour, or for measuring the impact of the waves on off-shore structures such as oil platforms or bridge pillars. It is also possible to use a porous volume to model the beach and study wave dissipation on the coast.

XFlow multiphase capabilities allow hydrodynamic analysis on the submerged boat region and aerodynamic analysis on the wind exposed region to be performed at the same time. This possibility to simulate both the interaction of the air and water with the boat makes XFlow suitable for sailing applications where both physics are closely related. Moreover, co-simulations with Abaqus or other structural solvers (through Open FSI and FMI standard) are available in XFlow which even allows inclusion of the sail deformation in this kind of application.