AFT Blog

To define any transient event in AFT Impulse or AFT Fathom XTS the application must know when it begins. To do so, the user should know how time and event logic is approached in AFT’s transient solvers. In this article, we will discuss the three different time bases used in the applications, the selection of a single or repeating event, and the many possible triggering events that can start the user defined transient. The user defines these items in the Initiation of Transient section of the junction’s Transient tab. The requirements for each junction can vary, but the general approach applies...

One of the new features in AFT Fathom 9 was the ability to model equivalent lengths instead of K factors for various types of fittings. Since AFT Fathom's existence, the standard K factor loss models have been used to quantify the pressure losses across a fitting such as an elbow, a valve, etc.  One of the reasons why the K factor method is very useful is because it is broad and applicable to a wide range of different fittings.  However, the equivalent length method is also a way that engineers will typically quantify the losses through their fittings and they will...