Large eddy simulation of flow through an axisymmetric sudden expansion
- Texas A & M University, College Station, TX (United States)
- Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Here, this study aims at investigating the inlet flow conditions of flow through an axisymmetric sudden expansion with an expansion ratio of 2.0. A series of large eddy simulations with the WALE model were conducted for different inlet Reynolds numbers ( Re) and turbulence intensities ($$u_{rms}/\bar{U}_m$$). The reattachment length, defined as the length measured downstream of the expansion where the flow direction is reversed adjacent to the wall ( Lr), was measured for each case. For widely studied inlet turbulence intensity values (TI), the simulation results are in good agreement with the experimental and numerical results reported in the literature. Parametric studies revealed that turbulence intensity affects the critical Reynolds number, marking the transition between the laminar and transition regions and the reattachment length. The critical Reynolds number was found to decrease with increasing turbulence intensity. A correlation expression is proposed. Additional analysis with proper orthogonal decomposition was performed to enhance the understanding of complex flow structures downstream of the expansion. Finally, an overall correlation expression for the reattachment length was obtained for 500 ≤ Re ≤15 000 and 0.2 ≤ TI (%) ≤ 20. For a given turbulence intensity, the reattachment length can be expressed for laminar and turbulent regions as a function of the Reynolds number. The reattachment length in the transition region can be expressed as a fractional average of reattachment lengths for laminar and turbulent flows.
- Research Organization:
- Idaho National Laboratory (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- Grant/Contract Number:
- AC07-05ID14517
- OSTI ID:
- 1924518
- Alternate ID(s):
- OSTI ID: 1871353
- Report Number(s):
- INL/JOU-22-66766
- Journal Information:
- Physics of Fluids, Journal Name: Physics of Fluids Journal Issue: 6 Vol. 34; ISSN 1070-6631
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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