Mechanical Engineering MS Thesis Defense by Mr. Milad Rakhsha
When: Thursday,
May 21, 2015
2:00 PM
-
4:00 PM
Where: Textiles Building 101E
Description: Mechanical Engineering MS THESIS DEFENSE by
Mr. Milad Rakhsha
DATE:
Monday, June 8th 2015
TIME:
2:00 a.m. – 4:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Computational Fluid Dynamics in OpenFOAM for Passive Control of Flow Separation On NACA 63-018 Airfoil Using Vortex Generators and Leading Edge Tubercles
ABSTRACT:
Fluid flow analysis is carried out numerically on passive geometries as the means to control flow separation on airfoils. Specifically, the effect of vortex generators (VGs) and leading edge tubercles (LETs) are investigated on NACA 63-018 airfoil using computational fluid dynamics (CFD). On one hand, a modified airfoil with double-sided VGs is analyzed for the sole purpose of ultra-high solidity hydrokinetic vertical axis turbines that operate predominantly in the stall region at low tip speed ratios. On the other hand, a modified airfoil with LETs is evaluated as an alternative option to VGs. To this aim, OpenFOAM is used as the CFD package to model the flow over the airfoil in pre-stall and stall regions. A structured mesh in blockMesh dictionary is developed, which provides a powerful framework to study various VGs geometries and their locations parametrically, as well as LETs waviness in terms of wavelength and amplitude. The numerical simulations are carried out using the steady-state solver, simpleFoam, over angle of attacks (α) ranging from 0◦ to 18◦, with the flow behaving as steady at low α and pseudo-steady at high α. For the low Reynolds number of interest in this study, namely 5×105, the k−ωSST turbulent model offers the best performance in comparison to other turbulent models. The VGs and LETs geometries are configured optimally at one angle of attack in the stall region. Subsequently, the optimal configurations are adopted and tested over 0◦ < α < 18◦ in order to characterize the lift and drag coefficients of the modified airfoil with VGs and LETs. Results show an increase in lift-to-drag ratio in the stall region using double-sided and non-submerged VGs located at 10% of the chord length. However, the modified airfoil with LETs did not show improvement in lift, drag, and lift-to-drag ratio in comparison to standard shape airfoil.
ADVISOR:
Dr. Raymond Laoulache (rlaoulache@umassd.edu, 508-999-8540)
COMMITTEE MEMBERS:
Dr. Sankha Bhowmick, Dr. Alex Fowler
Open to the public.
All MNE students are encouraged to attend.
For more information, please contact Dr. Raymond Laoulache (contact info above).
Thank you,
Sue Cunha, Administrative Assistant
508-999-8492
scunha@umassd.edu
Mr. Milad Rakhsha
DATE:
Monday, June 8th 2015
TIME:
2:00 a.m. – 4:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Computational Fluid Dynamics in OpenFOAM for Passive Control of Flow Separation On NACA 63-018 Airfoil Using Vortex Generators and Leading Edge Tubercles
ABSTRACT:
Fluid flow analysis is carried out numerically on passive geometries as the means to control flow separation on airfoils. Specifically, the effect of vortex generators (VGs) and leading edge tubercles (LETs) are investigated on NACA 63-018 airfoil using computational fluid dynamics (CFD). On one hand, a modified airfoil with double-sided VGs is analyzed for the sole purpose of ultra-high solidity hydrokinetic vertical axis turbines that operate predominantly in the stall region at low tip speed ratios. On the other hand, a modified airfoil with LETs is evaluated as an alternative option to VGs. To this aim, OpenFOAM is used as the CFD package to model the flow over the airfoil in pre-stall and stall regions. A structured mesh in blockMesh dictionary is developed, which provides a powerful framework to study various VGs geometries and their locations parametrically, as well as LETs waviness in terms of wavelength and amplitude. The numerical simulations are carried out using the steady-state solver, simpleFoam, over angle of attacks (α) ranging from 0◦ to 18◦, with the flow behaving as steady at low α and pseudo-steady at high α. For the low Reynolds number of interest in this study, namely 5×105, the k−ωSST turbulent model offers the best performance in comparison to other turbulent models. The VGs and LETs geometries are configured optimally at one angle of attack in the stall region. Subsequently, the optimal configurations are adopted and tested over 0◦ < α < 18◦ in order to characterize the lift and drag coefficients of the modified airfoil with VGs and LETs. Results show an increase in lift-to-drag ratio in the stall region using double-sided and non-submerged VGs located at 10% of the chord length. However, the modified airfoil with LETs did not show improvement in lift, drag, and lift-to-drag ratio in comparison to standard shape airfoil.
ADVISOR:
Dr. Raymond Laoulache (rlaoulache@umassd.edu, 508-999-8540)
COMMITTEE MEMBERS:
Dr. Sankha Bhowmick, Dr. Alex Fowler
Open to the public.
All MNE students are encouraged to attend.
For more information, please contact Dr. Raymond Laoulache (contact info above).
Thank you,
Sue Cunha, Administrative Assistant
508-999-8492
scunha@umassd.edu
Topical Areas: University Community, Mechanical Engineering