Aerodynamics is a division of fluid dynamics applied by engineers who wish to understand the forces generated on a body when placed within a fluid flow. By understanding the interaction between a solid body and its surrounding flow, it is possible to design aerodynamic shapes that are optimised for certain applications. Most applications of aerodynamics involve the design of lifting systems. For more information relating to aerodynamics and lifting systems refer to the article See How It Flies by John S Denker.
Computational Fluid Dynamics (CFD) is a branch of fluid mechanics that implements aerodynamic theory and numerical methods within a computational framework. The fluid flow being studied is broken down into minute cells and calculations are then performed to simulate the interaction of these cells with each other and with the surfaces of the solid bodies under analysis. The results of these calculations are processed to provide a prediction of the aerodynamic forces the body experiences. CFD greatly increases the efficiency of the design process. However, it is always necessary to validate CFD predictions using experiment and compare results to existing theory.
Cluster Management Software
CFD cases are run on a dedicated high performance CFD solving machine that is enabled with in-house written code to ensure that once a case finishes, a new case starts automatically.
Convergence Criteria Software
In-house developed software that whilst a CFD case runs, will monitor two selected variables and stop the case once these specific convergence criteria are met.
Cylindrical drum (or centrifugal) fan
The centrifugal fan is the fundamental component of all Entecho CAV craft. The CAV fan system includes the rotor, the drive system, the stator blades and the inlet and exhaust ducts. Wikipedia provides some general information relating to centrifugal fans.
The Entecho fan system is a highly advanced variant of the conventional centrifugal fan. As our design evolves we are continually improving the aerodynamic profile of the rotor blades, stator blades and ducts. This allows us to optimise the blade loading, increase the fan efficiency and consequently achieve maximum lift with minimum power and weight. Moreover, the fan is constructed using advanced composite manufacturing techniques further reducing weight.
The operation of the CAV cylindrical drum (or centrifugal) fan produces high pressure regions as a result of the air being accelerated through the intake and exhaust ducts. These regions are at a higher pressure than the air surrounding the craft. This means that these stronger regions of pressure are able to produce an upward or lifting force on the surface they are acting upon. The production of this force can be compared to that of two people pushing on opposite sides of surface. The person who is the strongest will move the surface in the direction that they are pushing. i.e. the high pressure region pushes against gravity and allows the craft to lift.
Lift can be defined as the aerodynamic force acting at right angles to the direction of motion of a body. However, it is more commonly known as the force which allows an aircraft to fly. For more information relating to lift refer to the article See How It Flies by John S Denker.
A rotor describes any rotating component of a machine. In the case of the CAV the rotor refers to the component of the cylindrical drum (or centrifugal) fan which rotates about the centre of the craft.
UDF’s (User Defined Functions)
Code that is imbedded into the CFD program that will control variables. In our simulations we use this method to assess one variable and adjust another variable depending on the outcome.