eVTOL (Electric Vertical Take-Off and Landing) & UAM (Urban Air Mobility): FEA & CFD Based Simulation for Ground Vibration Testing (GVT), Airworthiness Certification, Aerodynamics, Aeroacoustics and Crashworthiness

The VTOL, eVTOL and UAM market is constantly changing and evolving, so maintaining a competitive edge both within the industry and supporting mission effectiveness requires significant research and development activities. Enteknograte offers the industry’s most complete simulation solution for vertical-takeoff-and-landing (VTOL) aircraft. Our research and development procedure has required a blend of qualities such as ambition, drive and commitment as well as more tangible assets such as specialist engineering skills, rapid development through simulation techniques, supreme electronics expertise and a ruthless quest for performance and reliability.

The level of partnership and support for Developing a leading edge VTOL, eVTOL and UAM system FEA and CFD simulations that our customers get is just as important to us. We are investing time and resources to ensure customers receive support and service that is of the same, highest possible standards as the reliability and performance.

Increase efficiency, reduce noise, costs, and time-to-market of rotorcraft and eVTOL vehicles with an integrated design, simulation and optimization process

  • Leverage an integrated design and analysis process to develop preliminary VTOL aircraft designs that maximize propulsion efficiency in hover, maximize aerodynamic efficiency in cruise and minimize noise over the entire flight envelope.
  • Use high-fidelity fluid dynamics simulation in an optimization loop to maximize propulsion efficiency and minimize noise in hover.
  • Reduce blade-vortex interaction and loads acting on the control surfaces during conversion.
  • Design for low-noise manuevers.
  • Analyze the acoustic impact in a urban environment during take-off and landing.
  • Reduce product development costs and reduce time-to-market using digital simulations to predict performance early in the design cycle rather than physical tests in the late stages of development
VTOL e-VTOL UAM Acoustics Aeroacoustics aerodynamic Noise- Electric Vertical Take-Off & Landing CFD FEA Acoustics Crash Ansys Abaqus Nastran Siemens MSC Hexagon 2

Vibroacoustics performance assessment of aircraft panels in low, mid and high frequency regimes

A true VTOL system design has complex challenges, particularly designing for a high thrust for hover while also reducing drag for cruise. In simple terms, you are designing a helicopter and forward-flying aircraft in the same product.

Vibroacoustic (VA) characteristics, namely sound transmission loss, overall sound pressure levels of aircraft panels made up of different materials such as aluminum, composites and fiber metal laminates can be analyzed with optimization approach for aircraft panels.

The investigation involves modeling of aircraft panels using finite element method (FEM) for low frequency, Boundary Element Method (BEM) for mid-frequency and statistical energy analysis (SEA) in high-frequency bands. To obtain the VA characteristics of the panels, twin chambers, namely source and receiver are numerically modeled, and the panels are placed in between them. This numerical study helps in understanding the VA behavior of aircraft materials and also minimizes the cost and time involved in conducting experiments.

Structures drone ODYSSEE AI & Machine Learning for CFD, FEA, Statistics, Data Mining, Data Fusion, Optimization and Robustness
Electrical Motor Design: Electromagnetic Finite Element Analysis Acoustic NVH & jmag cedrat flux maxwell Vibro-Acoustics Simulation MSC Actran ESI VA one abaqus ansys CFD, FEA, SEA & BEM

eVTOLs and UAM Crashworthiness certification

Occupant safety is an integral part of the design, development, and operation of urban air mobility (UAM) systems. Emergency landing conditions design requirements specified in (Code of Federal Regulations) (Certification standard ) may not provide the level of safety for eVTOL vehicles.

The successful implementation of the UAM market will require emergency landing concepts that address real-world safety expectations. An integrated safety development process will help you maintain survivable volume, minimize deceleration loads to occupants, maintain egress paths and evaluate retention items of mass.

Enteknograte engineers optimize eVTOL aircraft crashworthiness from the conceptual design stage using most advanced computational tools.
How multibody models and optimization tools can be used to define integrated safety concepts for:

  • Landing gear and airframe crashworthiness
  • High-energy absorbing seats, and advanced restraints
  • Cabin subfloor structures
  • Energy-absorbing landing and take-off sites
Simulia Abaqus cargo airplanes Composite Crash Test, Fracture & Damage, Blast & explosion, Impact & Penetration, Thermal Analysis, Drop Test, Acoustics and Vibro-Acoustics

Airworthiness certification with efficient aircraft ground vibration: Ground Vibration Testing (GVT)

Ground vibration testing (GVT) is a major milestone in the FAA aircraft certification process  and EASA.The main purpose of the test is to obtain experimental vibration data for the entire aircraft structure so you can validate and improve its structural dynamic models. Among other things, these models are used to predict flutter behavior and plan safety critical flight tests. Ground vibration testing is typically performed late in the development cycle, and due to the limited availability of the aircraft, there is pressure to get the test results as quickly as possible.

Aircraft structural design must be carefully verified to meet performance requirements but also guarantee safety. On one hand, stringent regulations for reduced emissions call for more lightweight structures such as composite materials and innovative aircraft architectures, which creates lots of uncertainty around structural dynamic performance. On the other hand, new urban air mobility concepts enabled by electric propulsion offer possibilities for disruptive vertical take-off and landing (VTOL) aircraft configurations. This calls for more engineering work to validate and tune the performance of such innovative designs.

The goal of Ground vibration testing is to test program-critical flutter simulation results and reduce the risk of flight flutter tests. More specifically, this large-scale modal test on the full aircraft serves to calibrate computer-based finite element (FE) models used for further flutter predictions. The results of the test are the modal parameters of the aircraft structure and include modal frequencies, damping values, mode shapes and scaling factors for a number of configurations. During the Ground Vibration Testing (GVT) campaign, structural coupling tests involving the flight control system are also performed to help calibrate the simulation models and control laws. These calibrated aero-servoelastic models are then used for flutter predictions to analyze the behavior of the aircraft throughout its flight envelope and reduce the risk of the flight flutter test.

Aeroservoelasticity (ASE) is a multidisciplinary technology dealing with the interaction of the aircraft’s flexible structure, the steady and unsteady aerodynamic forces resulting from the aircraft motion, and the flight control systems.




unmanned helicopter noise rotor aeroelastic Aerodynamic simulation CFD MSC Cradle ansys fluent siemens star-ccm+
Aerospace defence CFD FEA Acoustics Crash Ansys Abaqus Nastran Siemens MSC Hexagon 2
VTOL e-VTOL UAM aerodynamics - Electric Vertical Take-Off & Landing CFD FEA Acoustics Crash Ansys Abaqus Nastran Siemens MSC Hexagon 2
Acoustic analysis for electric motors vehicles NVH & Vibro-Acoustics Simulation MSC Actran ESI VA one abaqus ansys CFD, FEA, SEA & BEM 2
NVH Electric Motor e-NVH TESTING 2

Aeroacoustics Wind Tunnel Testing

The airframe noises generated by the landing gear, flaps, slats, or other high-lift devices are significant contributors to aircraft acoustic emissions, especially during the approach and landing phases. To help minimize aircraft noise pollution in the vicinity of airports, engineers need to evaluate and optimize the acoustic performance of aircraft concepts and models as early as possible.

Wind tunnel tests are effective to validate prediction models before the aircraft can fly. However, they are costly and require extensive test preparation time. We use advanced acoustics solvers for aeroacoustics engineering by using advanced solutions for highly efficient aeroacoustic wind tunnel testing.

Noise, Vibration and Harshness – NVH in eVTOL – (Electric Vertical Take-Off & Landing) and Electro-Motors

FEA based Simulation Design for Electromagnetic multiphysics environments has a significant benefits for noise, vibration and harshness (NVH) analysis of electrical machines and transformers. NVH is an important analysis required by manufacturers of motors used in hybrid/electric vehicles, appliances, commercial transformers and other applications where quiet operation is an essential design parameter. Two-way transient magnetostriction coupling enables the magnetostrictive forces to be added to the magnetic forces and coupled to a mechanical design to predict acoustic noise.

Results from Electromagnetics solver obtained from the transient electromagnetic simulation to calculate the forces which are directly mapped to Mechanical solvers through special  co-simulation algorithms for harmonic analysis. Optionally, an acoustic analysis can be performed to study noise. The forces from Electromagnetics solver are mapped as force vectors within the volume of the individual mesh elements, allowing a detailed and accurate form of mapping. This is because element-based mapping allows forces to be calculated for individual mesh elements, increasing the accuracy.

To optimize for NVH, our engineers use the forces from the EM analysis to perform advanced vibro-acoustic simulations. The forces are mapped to evaluate the structural dynamics response of the motor. Modal and harmonic stress coupling responses are important for simulating the NVH of an electric motor and for proper vibro-acoustic design of eVTOL – (Electric Vertical Take-Off & Landing). The harmonic analyses generate absolute magnitudes of vibrations and waterfall diagrams to get a complete picture of the motor’s acoustic profile.




Cabin Aerodynamics CFD Simulation Thermal Comfort Aeroacoustic analysis HVAC components fans blowers air channels

VTOL Cabin Thermal Comfort CFD Simulation

The passenger’s thermal comfort is an essential design-criterion for the air-conditioning and customization of a VTOL and eVTOL cabin. In industry, engineers conduct costly and time-consuming test series with specifically built cabin mock-ups to obtain some information about the expected passenger’s sensation of comfort already in the design process.

We use the CFD Simulation to predict the passenger’s comfort by means of advanced software such as MSC Cradle, OpenFoam,  Star-ccm+ and Ansys Fluent and to allow for an interactive layout of an optimized cabin. The CFD-computations of the air flow in the cabin’s interior and the flow through cabin air outlets is optimized with the help flow simulations to achieve design specifications.




airplane engine aerospace defence AeroAcoustics Simulation MSC Actran ESI VA one abaqus ansys CFD, FEA, SEA & BEM 2
Finite Element crash model with head injury criterion HIC belt airbag male dummy Medical and Biomedical Abaqus, Ansys Fluent, Star-ccm+, Ls-dyna, Matlab
Airworthiness Crashworthiness Certification Electric Vertical Take-Off Landing UAM eVTOL Aircraft Simulation CFD Finite elelemt fea ls-dyna abaqus ansys fluent star-ccm siemens msc actran noise fatigue
Battery pack thermal simulation - Siemens Star-ccm+ CFD Simcenter
Aerospace Seat Design Federal Aviation Administration (FAA) European Aviation Safety Agency (EASA) Finite Element crash ansys ls dyna abaqus pamcrash radioss Dynamic Comfort Simulation
PCB Board Modeling and Simulation Ansys HFSS Electromagnetic
High Temperature Fatigue Life FEA Simulation Abaqus Ansys Nastran Fe-safe Ncode Design
IPM Electromagnetic Thermal thermomechanical fea simulation electric motor ev electric vehicle Coupled CFD and FEA Multiphysics Ansys Maxwell, Simulia Opera, JMAG, Cedrat FLUX, Siemens MAGNET and SPEED
VTOL e-VTOL UAM crashworthiness design Finite Element Simulation Crash Test MSC dytran Ls-Dyna Abaqus PAM-CRASH

Real world Simulation: Combination of experience and advanced analysis tools

Calling upon our wide base of in-house capabilities covering strategic and technical consulting, engineering, manufacturing and analytical software development – we offer each of our clients the individual level of support they are looking for, providing transparency, time savings and cost efficiencies.
Enteknograte engineers participate in method development, advanced simulation work, software training and support. Over experiences in engineering consulting and design development, enables Enteknograte’s engineering team to display strong/enormous client focus and engineering experience. The Enteknograte team supports engineering communities to leverage CFD-FEA simulation softwares and methodologies. It leads to the creation of tailored solutions, aligned with the overall product development process of Enteknograte clients.

CAE Simulation: CFD, FEA, System Modeling, 1D-3D coupling

Integrated expertise covering every Equipment component analysis. From concept through to manufacture and product launch, and for new designs or Equipment modifications, we provide engineering simulation expertise across projects of all sizes. Simulation has become a key enabling factor in the development of highly competitive and advanced Equipment systems. CAE methods play a vital role in defining new Equipment concepts.




Finite Element Simulation of Crash Test and Crashworthiness with LS-Dyna, Abaqus and PAM-CRASH

Crashworthiness focuses on occupant protection to reduce the number of fatal and serious injuries. This research is responsible for developing and upgrading test procedures for evaluating motor vehicle safety. Crashworthiness research encompasses new and improved vehicle design, safety countermeasures and equipment to enhance occupant safety. Finite Element Analysis (FEA) has been the trend in virtual crash design over the last decade. The predictive capabilities of FEA allow engineers to fully understand a crash event in a virtual environment, thus limiting the number of physical tests that need to be executed and thus saving costs.

Aerospace Seat Design: Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA)

In the United States, the Federal Aviation Administration (FAA) sets the standards for aerospace seat design regulations through its Technical Standard Orders (TSOs) and Federal Aviation Regulations (FARs). By using FEA according to FAA, our engineers can simulate the structural behavior of an aircraft seat and predict its response to various loading scenarios, including vibration , fatigue life, crash and impact conditions. In Europe, the regulations governing aerospace seats are defined by the European Aviation Safety Agency (EASA) which outlines the airworthiness standards that must be met for certification of large airplanes, including the design and testing of aircraft seats.

Passenger’s Thermal and Acoustic Comfort

CFD Simulation for Thermal Comfort & Aeroacoustic analysis of HVAC components, fans, blowers and air channels
The passenger’s thermal and acoustic comfort is an essential design-criterion for the air-conditioning and customization of a cabin. In industry, engineers conduct costly and time-consuming test series with specifically built cabin mock-ups to obtain some information about the expected passenger’s sensation of comfort already in the design process.

Battery Thermal Management: Simulation Based Design

Safe, efficient, and cost-effective designs of Electric Vehicles (EVs) batteries become more important. Lithium-ion batteries are the mainstream battery solution for today’s EVs but are sensitive to their operational thermal conditions. Therefore, thermal simulation of these battery packs is paramount in the designing phase, which includes consideration of heat production by battery electro-chemistry, internal resistivity and cooling, EV cooling system, etc.

Full Vehicle MultiBody Dynamics Simulation: Car Ride, Driveline, Engine and Tire MBD

With MultiBody Dynamic Simulation, you can perform various analyses on the vehicle to test the design of the different subsystems and see how they influence the overall vehicle dynamics. This includes both on- and off-road vehicles such as cars, trucks, motorcycles, buses, and land machinery. Typical full vehicle analysis includes handling, ride, driveline, comfort, and NVH. Automotive models are also used for Realtime applications (HiL, SiL, and MiL). We can also examine the influence of component modifications, including changes in spring rates, damper rates, bushing rates, and anti-roll bar rates, on the vehicle dynamics.

Robots Dynamics & Performance Assessment: Coupled MBD & FEA Simulation-Based Design

Robot designers can increase the performance of their products by using Coupled FEA and MBD software such as Ansys, Abaqus, Simpack and MSC Adams multibody simulation (MBS) software to simulate the transient dynamic behavior of the complete robot mechanism and control algorithm.

Coupled Multibody Dynamics & Control Systems

Controls are essential to operating systems such as air management systems, flight controls, and landing gear extension/retraction systems. Controls simulation allows us to predict the performance of controls subjected to numerous configurations. With controls simulation, the complexity of a controls system can be expressed in an easy to understand schematic form and the necessary differential equations used to define the system can be solved.

Multibody Dynamics & NVH (Noise, vibration, and harshness)

Noise, vibration, and harshness (NVH) are critical factors in the performance of many mechanical designs but designing for optimum NVH can be difficult. While strength and durability limits are being pushed further and further, requirements for noise reduction are becoming more stringent. In addition, focus is increasingly being placed on transmission and powertrain noise because other sources could be reduced meanwhile.

Electromagnetic Multiphysics

FEA & CFD Based Simulation Including Thermal Stress, Fatigue, and Noise, Vibration & Harshness – NVH for Electric Motors
Enteknograte Finite Element Electromagnetic Field simulation solution which uses the highly accurate finite element solvers and methods such as Ansys Maxwell, Simulia Opera, Simulia CST, JMAG, Cedrat FLUX, Siemens MAGNET and COMSOL to solve static, frequency-domain, and time-varying electromagnetic and electric fields includes a wide range of solution types for a complete design flow for your electromagnetic and electromechanical devices in different industries.

Integrated Artificial Intelligence (AI) & Machine Learning - Deep Learning with CFD & FEA Simulation

Machine learning is a method of data analysis that automates analytical model building. It is a branch of Artificial Intelligence based on the idea that systems can learn from data, identify patterns and make decisions with minimal human intervention. With Artificial Intelligence (AI) applications in CAE, that is Mechanical Engineering and FEA and CFD Simulations as design tools, our CAE engineers evaluate the possible changes (and limits) coming from Machine learning, whether Deep Learning (DL), or Support vector machine (SVM) or even Genetic algorithms to specify definitive influence in some optimization problems and the solution of complex systems.

Noise, Vibration & Harshness – NVH for Electric Motors

To optimize for NVH, our engineers use the forces from the EM analysis to perform advanced vibro-acoustic simulations. The forces are mapped to evaluate the structural dynamics response of the motor. Modal and harmonic stress coupling responses are important for simulating the NVH of an electric motor and for proper vibro-acoustic design of electric vehicles (EVs). The harmonic analyses generate absolute magnitudes of vibrations and waterfall diagrams to get a complete picture of the motor’s acoustic profile.

Electric Motors Cooling

Coupled Electromagnetic Solver with Finite Element & CFD Based Multiphysics simulation
Our FEA and CFD based multiphysics simulation design provides electronics cooling simulation products for chip, package and board thermal analysis as well as thermo-mechanical stress analysis. Multiphysics simulation tools help our customers to enhance reliability of the entire electronic system by managing excessive heat that can otherwise lead to increasing leakage and electromigration failure. Electric motors cooling becomes critical as we want to move to higher power, high-efficiency equipment.

Ansys HFSS: Multipurpose High Frequency Electromagnetic Field Simulator

RF, Microwave, Advanced Driver Assistance Systems (ADAS), Multipaction, and Electromagnetic Interference and Compatibility (EMI/EMC)
Ansys HFSS is a 3D electromagnetic (EM) simulation software for designing and simulating high-frequency electronic products such as antennas, antenna arrays, RF or microwave components, high-speed interconnects, filters, connectors, IC packages and printed circuit boards. Engineers worldwide use Ansys HFSS software to design high-frequency, high-speed electronics found in communications systems, advanced driver assistance systems (ADAS), satellites, and internet-of-things (IoT) products.

Ansys Maxwell: Low-Frequency Electromagnetic Simulation for Electric Machines

Ansys Maxwell is an electromagnetic field solver for electric machines, transformers, wireless charging, permanent magnet latches, actuators, and other electromechanical devices. It solves static, frequency-domain and time-varying magnetic and electric fields. Maxwell also offers specialized design interfaces for electric machines and power converters. It includes 3-D/2-D magnetic transient, AC electromagnetic, magnetostatic, electrostatic, DC conduction and electric transient solvers.

NVH & Acoustics for Hybrid & Electric Vehicles

In NVH Engineering and simulation of Hybrid/Electric Vehicles, the noise from tire, wind or auxiliaries, which consequently become increasingly audible due to the removal of the broadband engine masking sound, should be studied. New noise sources like tonal sounds emerge from the electro-mechanical drive systems and often have, despite their low overall noise levels, a high annoyance rating. Engine/exhaust sounds are often used to contribute to the “character” of the vehicle leads to an open question how to realize an appealing brand sound with EV.

Heat Transfer and Thermal Analysis: Fluid-Structure Interaction with Coupled CFD and Finite Element Based Simulation

We analyze system-level thermal management of vehicle component, including underhood, underbody and brake systems, and design for heat shields, electronics cooling, HVAC, hybrid systems and human thermal comfort. Our Finite Element (LS-Dyna, Ansys, Abaqus) and CFD simulation (Siemens Start-ccm+, Ansys Fluent , Ansys CFX and OpenFoam) for heat transfer analysis, thermal management, and virtual test process can save time and money in the design and development process, while also improving the thermal comfort and overall quality of the final product.

Acoustics and Vibration: FEA and CFD for AeroAcoustics, VibroAcoustics and NVH Analysis

Noise and vibration analysis is becoming increasingly important in virtually every industry. The need to reduce noise and vibration can arise because of government legislation, new lightweight constructions, use of lower cost materials, fatigue failure or increased competitive pressure. With deep knowledge in FEA, CFD and Acoustic simulation, advanced Acoustic solvers and numerical methods used by Enteknograte engineers to solve acoustics, vibro-acoustics, and aero-acoustics problems in automotive manufacturers and suppliers, aerospace companies, shipbuilding industries and consumer product manufacturers.

FEA Based Composite Material Design and Optimization: MSC Marc, Abaqus, Ansys, Digimat and LS-DYNA

Finite Element Method and in general view, Simulation Driven Design is an efficient tool for development and simulation of Composite material models of Polymer Matrix Composites, Metal Matrix Composites, Ceramic Matrix Composites, Nanocomposite, Rubber and Elastomer Composites, woven Composite, honeycomb cores, reinforced concrete, soil, bones ,Discontinuous Fiber, UD Composit and various other heterogeneous materials.

Aerodynamics Simulation: Coupling CFD with MBD, FEA and 1D-System Simulation

Aerodynamics studies can cover the full speed range of low speed, transonic, supersonic and hypersonic flows as well as turbulence and flow control. System properties such as mass flow rates and pressure drops and fluid dynamic forces such as lift, drag and pitching moment can be readily calculated in addition to the wake effects. This data can be used directly for design purposes or as in input to a detailed stress analysis. Aerodynamics CFD simulation with sophisticated tools such as MSC Cradle, Ansys Fluent and Siemens Star-ccm+ allows the steady-state and transient aerodynamics of heating ventilation & air conditioning (HVAC) systems, vehicles, aircraft, structures, wings and rotors to be computed with extremely high levels of accuracy.

Finite Element Analysis of Durability and Fatigue Life

Vibration Fatigue, Creep, Welded Structures Fatigue, Elastomer and Composite Fatigue with Ansys Ncode, Simulia FE-Safe, MSC CAEFatigue, FEMFAT
Durability often dominates development agendas, and empirical evaluation is by its nature time-consuming and costly. Simulation provides a strategic approach to managing risk and cost by enabling design concepts or design changes to be studied before investment in physical evaluation. The industry-leading fatigue Simulation technology such as Simulia FE-SAFE, Ansys Ncode Design Life and FEMFAT used to calculate fatigue life of multiaxial, welds, short-fibre composite, vibration, crack growth, thermo-mechanical fatigue.

Additive Manufacturing and 3D Printing

FEA Based Design and Optimization with Simufact, Abaqus, ANSYS and MSC Apex for powder bed fusion (PBF), directed energy deposition (DED) and binder jetting processes
With additive manufacturing, the design is not constrained by traditional manufacturing requirements and specific number of design parameters. Nonparametric optimization with new technologies such as Artificial Intelligence in coupled with Finite Element method, can be used to produce functional designs with the least amount of material. Additive manufacturing simulations are key in assessing a finished part’s quality. Here at Eneteknograte, dependent of the problem detail, we use advanced tools such as MSC Apex Generative Design, Simufact Additive, Digimat, Abaqus and Ansys.

Rotors Aerodynamic Simulation via Coupled FEA (MBD)/CFD Method: Aeroelastic Behavior Assessment

The blade vortex interactions (BVI) generate high load peaks and represent one of the main noise sources of a helicopter. In contrast to the rotors the flow around the fuselage is basically incompressible and many helicopters have a blunt body with large flow separations behind the fuselage. Depending on the flight conditions there may be strong interactions between main and tail rotors, rotor head, fuselage and the empennage, e.g. the tail shake phenomenon which is mainly caused by separations behind the rotor head.

Aerodynamic Noise Simulation

Sound caused by pressure oscillation of fluid, such as wind noise, and sound caused by resonance can be predicted using Large Eddy Simulation (LES) and a weak compressible flow model. A Fast Fourier Transform calculation can be used within the CFD software to predict the frequency of noise. Predicting the noise generated by complex flows from steady CFD solutions allows us to study the noise generated by turbulent flows from CFD solutions.

Drone Aerodynamic & Acoustic Simulation Based Design

For drone dynamics, the acoustics and noise challenge is to design disc loading, rotor tip speed, propeller interactions and vehicle scattering in such a way that the overall in-situ noise levels are reduced. It is a multidisciplinary issue, calling for the combined use of various simulation techniques.


We pride ourselves on empowering each client to overcome the challenges of their most demanding projects.

Enteknograte engineering team use advanced CAE software with special features for mixing the best of both FEA tools and CFD solvers: CFD codes such as MSC Cradle, Ansys Fluent, Siemens StarCCM+, OpenFoam and FEA Codes such as ABAQUS, Ansys, Nastran, LS-Dyna and Actran for Acoustics and VibroAcoustics simulations.