In recent years, engine manufacturers have strived to increase engine efficiency to reduce fuel consumption and emissions, for competitiveness and to meet strict government regulations. These advancements have led to highly stressed engine parts, in particular the crankshaft hydrodynamic bearings.

Narrow gaps are present in rotating and reciprocating machinery such as turbines, compressors, pistons, and gear pumps. These narrow gaps are often essential for the operation of the machinery, as leakage of the working fluid through the narrow gap provides lubrication between the moving parts, and these narrow gaps frequently are moving. Narrow gaps can also be used in the computational fluid model although not seen in the physical problem. This occurs in models with solid-to-solid contact. For example, consider the reed valve shown in Figure 1. Reed valves are a type of check valve that restrict flow to a single direction, opening and closing under changing pressure on each face. When the reed valve is open, fluid flows from the inlet port to the top chamber. When the reed valve is closed, solid-to-solid contact between the reed valve and the inlet port seat prevents flow. (a)Reed valve is open. Fluid flows from the inlet port to the top chamber. (b) Reed valve is closed. There is no fluid flow. Figure 1  Fluid flow through a reed valve In the analysis of a reed valve, see here for an example of a piston with a suction reed valve, fluid elements must be

The animation is a simulation of the flow field when one car passes another in a tunnel. The simulation demonstrates the use of the sliding mesh interface feature, which will be available in version 8.2 of ADINA.

The below animation depicts an axisymmetric model of a mono-tube gas shock absorber, with its schematic beside it. The piston inside the casing pushes its way through the oil (the hydraulic fluid which in reality is a mixture of oil and gas) creating resistance as the oil is pushed through the small holes in the piston. The contact between the piston (solid model) and the casing is modeled by specifying a friction coefficient, which is usually very small due to the lubrication provided by the oil.

In ADINA v. 9.0, we introduced a new graphics engine that enables fast visualization and manipulation of large models in the ADINA User Interface (AUI).   Since then, we have continued to make improvements so that FGM supports many more capabilities within the AUI. One recent major improvement is the creation of animations using the fast graphics engine which we will highlight in this Tech Brief. Animations created in standard graphics mode are essentially sequences of 2-D images displayed on the screen. Hence, during playback, the animation cannot be rotated or zoomed. In contrast, animations created in FGM are true 3-D animations which can be rotated, zoomed and moved to view any particular part of the model during playback as illustrated below. The first movie illustrates the ability to pause the animation and examine certain parts by zooming and rotating the model. In the second movie, the model is rotated and zoomed while the animation is in progress. https://blog.bentley.com/wp-content/uploads/3-d-animations-with-the-adina-fast-graphics-engine.mp4https://blog.bentley.com/wp-content/uploads/3-d-animations-with-the-adina-fast-graphics-engine_1.mp4 In ADINA v. 9.7, the following additional improvements were made to the creation and saving of 3-D animations in FGM. Animations can be created on multiple mesh plots A new playlist feature is available to manage multiple animations Animations stored in a

ADINA 8.1 has several enhancements to its cyclic symmetry analysis capabilities. The sparse and iterative solvers can now be used to solve cyclic problems. The primary cyclic component is no longer required to be aligned with the X-Y plane, and the axis of cyclic symmetry can have any orientation in space.