Aerodynamics of complex moving 3D objects

12 December 2013

 

Capvidia is proud to announce a new type of CFD simulations successfully analyzing aerodynamics of complex moving 3D objects as human beings. This new FlowVision capability has a direct implementation in different sport disciplines where aerodynamics or hydrodynamics have influence on the potential results. Different sport disciplines are of particular interest because computer simulation can help to develop new training methods based on the athletes’ individual performance and individual characteristics of movements.

 

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Sources and secondary flows formation on the athlete’s body

Until recently, the published research results were based on investigation of quasi-stationary problem –aerodynamic simulation was performed at fixed athletes’ positions trying to mimic a real movement.  Such a simulation does not fully take into account the interaction of a moving body with the stream of air or water and does not give a full picture of the real physical phenomena.

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Pressure distribution in the different phases of movement

 

Developed by Capvidia/TESIS approach combines standard moving objects capturing technology and FlowVision capability to simulate moving bodies’ movement in the computational domain:

  • Motion is captured using motion capture technology form Qualisys
  • A sequence of moving bodies is analyzed in CFD simulation software FlowVision
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A sequence of moving bodies

 

The moving body in the CFD simulation domain:
The technology developed by Capvidia/ TESIS for simulation of moving bodies is based on a mathematical modeling of the flow around moving and deformable bodies relative to the fixed boundaries of the computational domain. The motion of the bodies in space can be arbitrary and is defined by translational-rotational with six degrees of freedom.
For the first time flow simulation technology including moving bodied was presented by Capvidia/TESIS in 1999 and applied for solving various industrial problems such as:

  • shipbuilding  applications — ship movement on the wavy water , submerging of submarine, etc.;
  • energy applications — simulation of screw compressors, valve trains, etc.; 
  • aerospace applications — simulation of wing mechanization, opening of landing gear, etc.;
  • multi-physics simulation aerospace applications

Motion Capture

Motion capture technology has gained its popularity in the gaming and film industry. It allows animating movements and facial expressions of virtual characters, created with the use of computer graphics (CGI) based on observation of movements and facial expressions of real people equipped with special optical sensors. The recording is made with help of markers installed on the human body. The movement of markers is registered by the measurement system.  The resulting data set provides animation of the movements which can be applied on the virtual character created in the computer.
The movements recording was performed with specialized optical motion registration system from Qualisys, allowing recording moving objects in the air and under the water.


The process consists of the following steps:

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  • scanning moving athlete’s movements with  (motion capture system
  • generation of kinematic model in form of an animated skeleton frames, which are combined with the 3D athlete scanned representation (volume defined by a mesh surface). The weights of the skeleton movement are transferred on the volume skin grid to get smooth body movement (animation).
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Moving skeleton combined with the 3D scanned skater body
Watch Moving sceleton from Motion Capture

 

  • Animated 3D model is being passed to FlowVision for simulation of the external aerodynamics.
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Sources and secondary flows formation around the skater body
Watch moving skater sideview simulation

 

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Watch swimming simulation

 

The above described multi-disciplinary simulation concept allows to analyze complex moving objects with variable in time 3D shape. It offers a practical solution for investigation of flow influence in different sports disciplines where performance and results are dependent on aerodynamics or hydrodynamics characteristics. We used the described technology to investigate and optimize training of bobsleigh, and skeleton teams. At this moment the investigation involves sky-jump. There are potential applications in swimming and cycling to mention some other perspective directions.

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