SAWAE2020, SouthEast Asia Workshop on Aerospace Engineering
th
29 Jan. 2021 Tainan, Taiwan
Numerical study on drag crisis phenomenon of flow over teardrop model
Le Thi Hong Hieu*1,2, Huynh Tan Phuoc, 1,2 and Nguyen Ngoc Hien3
1
Department of Aerospace Engineering, Faculty of Transportation Engineering, Ho Chi Minh
University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City,
Viet Nam
2
Vietnam National University Ho Chi Minh City, Linh Trung ward, Thu Duc District, Ho Chi
Minh City, Vietnam
3
Royal Melbourne Institute of Technology University, Australia
Abstract
Drag is a common topic in everyday activities and academic research. Drag crisis, which
associates with the transition of boundary layers from laminar to turbulent, is a phenomenon
that can gain advantages when increase velocity to the critical value for the wing with airfoil
shape. Meanwhile, the appearance of laminar separation bubble (LSB) is thought for the
cause of drag crisis. The mechanisms, and structure as well as the influencing factors of
laminar separation bubble have also been comprehensively studied. The paper focuses on
the numerical approach to simulate three – dimensional (3D) teardrop model for the study of
aerodynamic characteristic and LSB mechanisms. Results from the open source code
OpenFOAM are compared to that of the experiments [1] and prove the pros of computational
fluid dynamics (CFD). The 3D simulation results are exploited to analyze the spectrum
velocity, spectrum pressure, … in the critical Reynolds regime, in which the drag crisis
occurs, from
to
. At the same time, the apperance of laminar
separation bubble in the critical Reynolds regime is also analyzed. The results highlight the
advantages of the transition SST turbulence model compared to the
turbulence
model in simulating the drag crisis phenomenon and the footprint of bubble formation.
Keywords: drag crisis, laminar separation bubble, teardrop model, RANS, turbulent model
, turbulent model transition SST
Reference
[1] P. Dong, "An experiment study about drag crisis phenomenon on teardrop model”,
National Cheng Kung University, Tainan,Taiwan, 2018.
Subject area: Aerodynamics, Computational Fluid Dynamics.
Figure 1. Streamlines at different Reynolds numbers
*Corresponding Author:
Le Thi Hong Hieu
Department of Aerospace Engineering, Ho Chi Minh City University of Technology
268 Ly Thuong Kiet, District 10, Ho Chi Minh City, Vietnam
Tel.: +84-902-166-271
Email: honghieu.le@hcmut.edu.vn