Large Eddy Simulation for Low Frequency Oscillations in Tail-Pipe Nozzle Solid Rocket Motors

2010 ◽  
Author(s):  
Qiao Zhang ◽  
Jun-wei Li ◽  
Wei-chen Wang ◽  
Ning-fei Wang
Keyword(s):  
Large Eddy Simulation ◽  
Low Frequency ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Tail Pipe ◽  
Eddy Simulation ◽  
Low Frequency Oscillations ◽  
Large Eddy ◽  
Solid Rocket

Large-Eddy Simulation of Vortex Shedding and Pressure Oscillations in Solid Rocket Motors

AIAA Journal ◽  
2020 ◽  
Vol 58 (12) ◽  
pp. 5191-5201
Author(s):  
M. Bernardini ◽  
M. Cimini ◽  
F. Stella ◽  
E. Cavallini ◽  
A. Di Mascio ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Vortex Shedding ◽  
Pressure Oscillations ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Solid Rocket

scholarly journals Large Eddy Simulation of Periodic Transient Pressure Fluctuation in a Centrifugal Pump Impeller at Low Flow Rate

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 311
Author(s):  
Renfei Kuang ◽  
Xiaoping Chen ◽  
Zhiming Zhang ◽  
Zuchao Zhu ◽  
Yu Li
Keyword(s):  
Large Eddy Simulation ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Low Frequency ◽  
Pump Impeller ◽  
Eddy Simulation ◽  
Inlet Flow Rate ◽  
Large Eddy ◽  
Centrifugal Pump Impeller

This paper presents a large eddy simulation of a centrifugal pump impeller during a transient condition. The flow rate is sinusoidal and oscillates between 0.25Qd (Qd indicates design load) and 0.75Qd when the rotating speed is maintained. Research shows that in one period, the inlet flow rate will twice reach 0.5Qd, and among the impeller of one moment is a stall state, but the other is a non-stall state. In the process of flow development, the evolution of low-frequency pressure fluctuation shows an obviously sinusoidal form, whose frequency is insensitive to the monitoring position and equals to that of the flow rate. However, inside the impeller, the phase and amplitude in the stall passages lag behind more and are stronger than that in the non-stall passages. Meanwhile, the strongest region of the high-frequency pressure fluctuation appears in the stall passages at the transient rising stage. The second dominant frequency in stall passages is 2.5 times to that in non-stall passages. In addition, similar to the pressure fluctuation, the evolution of the low-frequency head shows a sinusoidal form, whose phase is lagging behind that by one-third of a period in the inlet flow rate.

Large Eddy Simulation of Laminar and Turbulent Shock/Boundary Layer Interactions in a Transonic Passage

2020 ◽  
Author(s):  
Stephan Priebe ◽  
Daniel Wilkin ◽  
Andy Breeze-Stringfellow ◽  
Giridhar Jothiprasad ◽  
Lawrence C. Cheung
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Low Frequency ◽  
Boundary Layer Separation ◽  
Eddy Simulation ◽  
Turbulent Inflow ◽  
Wide Range ◽  
Large Eddy ◽  
Constant Radius ◽  
Structure Boundary

Abstract Shock/boundary layer interactions (SBLI) are a fundamental fluid mechanics problem relevant in a wide range of applications including transonic rotors in turbomachinery. This paper uses wall-resolved large eddy simulation (LES) to examine the interaction of normal shocks with laminar and turbulent inflow boundary layers in transonic flow. The calculations were performed using GENESIS, a high-order, unstructured LES solver. The geometry created for this study is a transonic passage with a convergent-divergent nozzle that expands the flow to the desired Mach number upstream of the shock and then introduces constant radius curvature to simulate local airfoil camber. The Mach numbers in the divergent section of the transonic passage simulate single stage commercial fan blades. The results predicted with the LES calculations show significant differences between laminar and turbulent SBLI in terms of shock structure, boundary layer separation and transition, and aerodynamic losses. For laminar flow into the shock, significant flow separation and low-frequency unsteadiness occur, while for turbulent flow into the shock, both the boundary layer loss and the low-frequency unsteadiness are reduced.

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