RPF ASBM Project

Assessment of the Performance of the ASBM Turbulence Closure in Biomedical Fluid Flows


The project is sponsored by the Research Promotion Foundation (RPF) of Cyprus. The project is part of the “Nikos Simeonides” 2010 prize for Excellence in Research, awarded to Prof. S. C. Kassinos (the coordinator of the project).  


The ASBM is an advanced Reynolds Averaged Navier-Stokes (RANS) model of turbulence that holds significant promise for improved turbulence predictions in complex engineering flows. Having originally been formulated at Stanford University, the ASBM has, over the last decade, been further developed at the Computational Sciences Laboratory (UCY-CompSci) of the University of Cyprus. The model allows improved flow predictions for many important benchmark cases, involving two-dimensional mean flow configurations, but has so far not been extensively tested in flows with three-dimensional effects, such as separation and re-attachment. However, a number of important applications, spanning diverse engineering fields, such as body-wing junctions in aerodynamics and airflow and particle deposition in the human respiratory system, involve strong three-dimensional effects. Therefore, an important next step in the continued development of ASBM is the validation, and if necessary further development of the model, for a number of benchmark cases involving internal flow with significant three-dimensional effects. To achieve this goal we compute a number of benchmark cases of increasing complexity leading finally to the computation of the flow in a simplified model of the human respiratory system.

Project Members

Prof. Stavros Kassinos (University of Cyprus, Department of Mechanical and Manufacturing Engineering)
Dr. Dimokratis Grigoriades (University of Cyprus, Department of Mechanical and Manufacturing Engineering)
Dr. Xavier Albets-Chico (University of Cyprus, Department of Mechanical and Manufacturing Engineering)
Mr. Fotos Stylianou (University of Cyprus, Department of Mechanical and Manufacturing Engineering)
Mr. Konstantinos Panagiotou (University of Cyprus, Department of Mechanical and Manufacturing Engineering)

Collaborative Members

An ongoing collaboration exists with the following members:

Prof. Rene Pecnik (Delft University of Technology, Process and Energy)
Dr. John O’Sullivan (The University of Auckland, The Department of Engineering Science)
Prof. Karthik Duraisamy (Stanford University, Department of Aeronautics and Astronautics)
for more information see the joint website:

Project Purpose

The project aims at the further development and validation of the Algebraic Structure-Based Model (ASBM) for three-dimensional internal turbulent flows, with the long term objective to use the model in simulations of air flow and aerosol deposition in the human respiratory system. 

High-Level Objectives

1) To train the Young Researcher on turbulence modeling, and in particular on the ASBM closure,
2) To refine the ASBM closure for internal flows with strong three-dimensional effects,
3) To promote the adaptation of the ASBM in a number of engineering fields, such as in biomedical engineering.

Scientific and Technological Objectives

1) To optimize the existing implementation of ASBM in a highly scalable, MPI-based, parallel Navier-Stokes solver (CDP2.4), on structured/unstructured grids, for efficiency and stability. 2) To carry out a systematic validation of the ASBM in a progression of internal turbulent flows of increasing complexity and with significant three-dimensional effects that have traditionally challenged RANS closures. These cases are: a. Fully-developed turbulent flow in a pipe. b. Fully-developed turbulent flow in a square-duct. c. Fully developed flow in a bifurcating pipe (simplified model of trachea and bronchi). 3) To refine the model by addressing potential shortfalls identified during the testing phase. 4) To collaborate with international individual researchers for the thorough validation of the model and for exchange of knowhow on the numerical implementation of the ASBM, thus further promoting the international dimension of the ASBM.


UCY-CompSci is organizing a workshop in Cyprus during which the main scientific and technological outcomes of the project will be presented. The workshop is arranged on 23 of May 2014 at 10:00. It will take place at the conference room at the Nireas building 96 Kyrenias street, Aglantzia.

Turbulent Pipe Flow

DNS of a fully developed turbulent pipe flow, at Re_bulk= 5300 and Re_tau=180. Contours of instantaneous streamwise velocity U_x. Non- dimensionalization is carried using the bulk velocity (u_bulk=1), and radius of the pipe (R=1). The upper part of the video is an x-y cross-section (at z/R=0), while the lower part of the video is a z-y cross-section (at x/R=7.5).

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