Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure

In summary, Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure is a simulation tool used for computational fluid dynamics to model fluid-filled cavities under uniform pressure. It works by using finite element analysis to discretize the fluid domain and takes into account boundary conditions and material properties. The significance of studying this is to optimize designs and ensure structural integrity in engineering applications. Benefits include accurate modeling and time-saving, but limitations include the need for proper calibration and understanding of its capabilities.
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Hi Dear All,

Hope I can have some suggestions to tackle this weird problem.
I have an axisymmetric ball, with CAX8R elements being inflated with hydrostatic fluid elements.
Fluid elements surface is put on the internal surface of the ball (defined by picking the surface of the CAX8R elements).
BC:
Y direction-only allowed for nodes on Y axis.
8 degree of freedom pressurized on the reference node (center of the half circle, cavity reference node), fluid is water.

The internal cavity pressure reaches its expected value at the end of the step. This is very fine and straight forward.
But I see one thing which is rather unrealistic and annoying: The ball moves downward!

My only explanation is that there is something wrong with the normals of the fluid elements, may be not all of them are outward?
But since the surface is automatically defined by abaqus, I don't really know if this is the case and/or how I can tackle it.

Please let me know if I can provide more details.

Thanks a lot!
Amir
P.S: Attached: input file and a jpeg of this simple geometry.
Just change the extension of the pdf file to zip!
 

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  • #2
</code>The most likely cause of this phenomenon is due to the fact that the contact between the inner surface of the ball and the fluid element surface is not strong enough. This can happen when the contact surfaces are not properly aligned or when the contact stiffness is inadequate. To fix this, you need to make sure that the contact surfaces are properly aligned and that the contact stiffness is adequate. You can try increasing the contact stiffness or using a different contact algorithm in Abaqus. You can also try using an appropriate mesh size to ensure the contact surfaces are properly aligned. Finally, you can also try adding more contact elements to the model to increase the contact strength.I hope this helps. Good luck!
 

FAQ: Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure

1. What is Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure?

Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure is a simulation tool used in the field of computational fluid dynamics to model the behavior of a fluid-filled cavity under the influence of a uniform hydrostatic pressure. It is a part of the Abaqus software suite, which is commonly used in engineering and scientific research for finite element analysis.

2. How does Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure work?

Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure works by using finite element analysis to discretize the fluid domain into small elements, allowing for the simulation of fluid flow and pressure distribution within the cavity. The software also takes into account the boundary conditions and material properties specified by the user to accurately model the behavior of the system.

3. What is the significance of studying fluid cavities under uniform hydrostatic pressure?

Studying fluid cavities under uniform hydrostatic pressure is important in various engineering applications, such as in the design of underwater structures or hydraulic systems. It allows for the prediction of fluid behavior and potential failure points, helping engineers to optimize designs and ensure structural integrity.

4. What are the benefits of using Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure?

The use of Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure provides numerous benefits, including the ability to accurately model complex fluid flow and pressure patterns, simulate different boundary conditions, and optimize designs for improved performance and safety. It also saves time and resources compared to physical experiments.

5. Are there any limitations to using Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure?

Like any simulation tool, there are limitations to using Abaqus: Fluid Cavity - Moving cavity under uniform hydrostatic pressure. These include the need for proper calibration and validation of the model, as well as the accuracy of the input parameters and assumptions made. It is important to fully understand the capabilities and limitations of the software before using it for a particular application.

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