Degradation of aerodynamic performances of two typical aerofoils under heavy rain: A comparative study using CFD simulation

2018 ◽  
Vol 20 (3) ◽  
pp. 325-332
Author(s):  
SUSHOVAN CHATTERJEE ◽  
JNANARANJAN ACHARYA ◽  
KRISHNA MURARI PANDEY
Keyword(s):  
Comparative Study ◽  
Cfd Simulation ◽  
Heavy Rain ◽  
Aerodynamic Performances

scholarly journals Ground Test and Numerical Simulation on Ground Effect of Ducted Propeller System

2020 ◽  
Vol 38 (5) ◽  
pp. 1038-1046
Author(s):  
Yangping Deng ◽  
Baigang Mi ◽  
Hao Zhan ◽  
Fei Cao
Keyword(s):  
High Pressure ◽  
Cfd Simulation ◽  
Ground Effect ◽  
Power Characteristics ◽  
Pressure Zone ◽  
Ducted Propeller ◽  
Aerodynamic Performances ◽  
Ground Test ◽  
Simulation Results ◽  
High Pressure Zone

The aerodynamic performances of a ducted propeller system applied in a manned vertical takeoff and landing aircraft considering the ground effect are investigated. Based on the ground test and CFD simulation combined with sliding mesh technique, the thrust and power characteristics of the ducted propeller under different heights between the duct and ground are compared and analyzed, and the influence mechanism of the ground effect on the aerodynamic performance of the ducted propeller is detailed analyzed based on the CFD simulation results. The test and simulation results show that, the ground near the ducted propeller leads to a high-pressure zone to block the jet flow through the outlet of the duct, while an upward rebounded flow with the vortex rings is also generated to affect the aerodynamic forces and powers of both the duct and propeller. As the influence of the high-pressure zone, the thrust of the propeller increases. However, the thrust of the duct decreases when the rebounded flow is inhaled again into the duct. With the increase of the heights between the ground and the ducted propeller, the ground effect is weakened, and the power of the system recovers more quickly than the thrust. In general, the ground effect seriously affect the aerodynamic efficiency of the ducted propeller in near ground hover state, which should be mainly considered in the process of aerodynamic and conceptual design.

A Comparative Study of Combustion Models for Spark Ignition Engines Based on Experimentation and CFD Simulation

2010 ◽  
Author(s):  
Raouf Mobasheri ◽  
M. Sadegh Shahrokhi-Dehkordi
Keyword(s):  
Comparative Study ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Experimental Tests ◽  
Experimental Results ◽  
Nox Emission ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Flamelet Model ◽  
Combustion Models

Computational fluid dynamics (CFD) is able to significantly reduce the number of experimental tests and measurements and lower the development time and costs. However some parameters which are needed for CFD calculation must be achieved experimentally. In this paper, a comparative study was carried out to clarify the effect of three different combustion models on the prediction capability of combustion process and NOx emission on a modified 4-cylinder MPFI SI engine. Validation of the combustion model has been performed through comparing simulation data with the experimental results and a satisfactory agreement between them has been achieved in terms of combustion parameters and NOx emission. The results show that, applying appropriate constants of each combustion model including Eddy break up model (Ebu), Probability density function (Pdf) and Coherent flamelet model (Cfm) causes the computational results to be in agreement with experimental results. Furthermore the results show that the nearest prediction in comparison with experimental results is by applying the Ebu model.

scholarly journals Comparative Study of Vortex-Induced Vibration of FRP Composite Risers with Large Length to Diameter Ratio Under Different Environmental Situations

2019 ◽  
Vol 9 (3) ◽  
pp. 517 ◽  
Author(s):  
Chunguang Wang ◽  
Shiquan Ge ◽  
Mingyu Sun ◽  
Zhirong Jia ◽  
Baomin Han
Keyword(s):  
Comparative Study ◽  
Oil And Gas ◽  
Cfd Simulation ◽  
Stress Distributions ◽  
Vortex Induced Vibration ◽  
Frp Composite ◽  
Composite Layers ◽  
Large Length ◽  
Offshore Oil And Gas ◽  
Offshore Oil

The increasing attraction of crude resources on the ocean floor leads to the development of risers, which are an indispensable component of an offshore oil and gas exploitation structure. High-grade steel is normally utilized for risers, however, fiber reinforced polymer (FRP) composite risers have become a feasible and economical alternative due to the desirable properties of the material. A comparative study of vortex-induced vibration (VIV) of FRP composite risers with two designed geometries were conducted and an X80 steel riser was used as the benchmark. The length to diameter ratios of all three risers were set to 100 and their VIV responses under different environmental situations, including the natural frequencies, global displacements, global stresses and the stress distributions in every composite layers, were obtained using computational fluid dynamics (CFD) simulation with coupled fluid–structure interaction. The VIV characteristics of both FRP composite risers and their distinction compared with that of steel risers were analyzed and discussed. From this paper, the dynamic characteristics in different environmental situations of VIV for FRP composite risers can be further understood.

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