In this tutorial,
the cavitation characteristics of a hydrofoil is investigated and compared to experimental data. The capability for multi-dimensional
simulation of cavitating flows is of critical importance for efficient
design and performance of many engineering devices. Cavitation refers to the formation of vapor filled cavities
at low pressure regions of a flow field and their subsequent implosion
while passing through high pressure regions of the flow field. Their
phenomenon generally is undesirable causing erosion of propellers,
pumps and other solid bodies. They are however considered and used in a
beneficial way for a number applications including ultrasonic cleaning,
water purification, high speed underwater propulsion and even to
produce high temperatures and pressures for initiating thermonuclear
fusion reaction.
Cavitation generally refers to the formation of vapor filled cavities at low pressure regions of a flow field and their subsequent implosion while passing through high pressure regions of the flow field. Their phenomenon generally is undesirable causing erosion of propellers, pumps and other solid bodies. They are however considered and used in a beneficial way for a number applications including ultrasonic cleaning, water purification, high speed underwater propulsion and even to produce high temperatures and pressures for initiating thermonuclear fusion reaction. Therefore, the capability for multi-dimensional simulation of cavitating flows is of critical importance for efficient design and performance of many engineering devices. In this tutorial, the cavitation characteristics of an axisymmetric sharp edged orifice is investigated and compared to some analytical predictions.
The steady state conductive heat transfer to the air-gap between infinitely long concentric thick-walled cylinders is modeled and compared with an analytical solution. This is a step-by-step guided introductory tutorial for setting up a heat transfer model in CFD-ACE+.
In this tutorial, the geometry of a bent pipe is optimized. The bent section of the pipe must provide 90-degree change of direction for a fluid flowing through it. The objective is to determine the bend radius R that provides the minimal (optimal) pressure drop through the pipe.
Dielectrophoresis occurs because of the interaction between the induced dipole and the electric field. The interaction creates a net force, which depends on both the gradient of the electric field and electrical properties (permittivity and conductivity) of the particle and the media. The net force applies on partices, charged or not, and drives them to move. This technique can be used in the analysis, manipulation, and separation of cellular scale and nanometer scale particles like cells, DNA etc.
Electrokinetic injection is an alternate method of loading DNA sample onto the capillary separation matrix for capillary electrophoresis compared to hydrodynamic or manual loading.This transfer is directly dependent on the magnitude and duration of voltage applied across the capillaries. This tutorial investigates the electrokinetic
injection and separation of analytes in a cross channel under the influence
of an electric field.
This simulation models a two-dimensional cross channel geometry
connecting four sample reservoirs. The process considered is
electroosmotic driven flow from reservoir 1 to reservoir 2. The model
examines the coupled fluid flow and electrostatic field at steady state. Electroosmotic flows are being considered for possible use in a number of biomedical applications involving flow in flow channels such as needless blood sampling for glucose testing.
In certain applications, different regions of the computational domain experience flow conditions that are so different that it is very difficult for a single solver to produce accurate results at the extremes. In many situations, such problems can be separated and solved using loosely coupled solvers. Each solver is chosen to provide highly accurate solutions for the prevailing flow conditions.
ESI's CFD-FASTRAN, a compressible flow solver, is ideally suited for high speed external aerodynamics problems and the multi-physics solver CFD-ACE+ is ideally suited for heat transfer problems involving conduction, convection (natural and forced) and radiation.
A large amount of aerodynamic heating is generated over hypersonic vehicles during re-entry. Thermal Protection System (TPS) materials are employed to prevent the heating from conducting into the internal cabin, which holds electronic devices, passengers and other vital components. As a time-dependent process, the material making up TPS is at a low temperature and “soaks up” the heat – the conductivity of the material transports the heat (from the vehicle surface) through the thickness. The material will also re-radiate some of the heat back to the flow – the amount depending on the emissivity of the material. A primary concern is to estimate the effects of aeroheating on the internal volume of the capsule and its effect on electronic devices, passengers and cooling systems. In this application, typically the external flow is hypersonic in nature, whereas the flow within the capsule is a very low speed flow dominated by natural convection. In addition, to hypersonic aerodynamic heating, several other physics including heat conduction, natural convection and radiation has to be accurately modeled. CFD-FASTRAN solves for the external hypersonic flow and CFD-ACE+ solves for heat conduction, convection and radiation. Exchange of heat flux/temperature data between FASTRAN and ACE occurs at defined interfaces.
The objective of this tutorial is to find the optimum bend radius R such that the pressure drop in the pipe is minimum for given a two-dimensional pipe with fixed velocity inlet.
