**A Study of the Transient Response of Duct Junctions: Measurements and Gas-Dynamic Modeling with a Staggered Mesh Finite Volume Approach**

### **Antonio J. Torregrosa \*, Alberto Broatch, Luis M. García-Cuevas and Manuel Hernández**

CMT–Motores Térmicos, Universitat Politècnica de València, 46022 Valencia, Spain; abroatch@mot.upv.es (A.B.); luiga12@mot.upv.es (L.M.G.-C.); maher12@mot.upv.es (M.H.)

**\*** Correspondence: atorreg@mot.upv.es; Tel.: +34-963-877-658

Academic Editor: Kuang-Chao Fan Received: 20 March 2017; Accepted: 2 May 2017; Published: 8 May 2017

**Abstract:** Duct junctions play a major role in the operation and design of most piping systems. The objective of this paper is to establish the potential of a staggered mesh finite volume model as a way to improve the description of the effect of simple duct junctions on an otherwise one-dimensional flow system, such as the intake or exhaust of an internal combustion engine. Specific experiments have been performed in which different junctions have been characterized as a multi-port, and that have provided precise and reliable results on the propagation of pressure pulses across junctions. The results obtained have been compared to simulations performed with a staggered mesh finite volume method with different flux limiters and different meshes and, as a reference, have also been compared with the results of a more conventional pressure loss-based model. The results indicate that the staggered mesh finite volume model provides a closer description of wave dynamics, even if further work is needed to establish the optimal calculation settings.

**Keywords:** duct junction; staggered mesh finite volume model; multi-port
