A design method was developed to specify the profile of the continuously variable Mach-number nozzle for the supersonic wind tunnel. The controllable contour design technique was applied to obtaining the original nozz...A design method was developed to specify the profile of the continuously variable Mach-number nozzle for the supersonic wind tunnel. The controllable contour design technique was applied to obtaining the original nozzle profile, while other Machnumbers were derived from the transformation of the original profile. A design scheme, covering a Mach-number range of3.0<Ma<4.0, was shown to illustrate the present design technique. To fully validate the present design method, computational fluid dynamics(CFD) analyses were carried out to study the flow quality in the test area of the nozzle. The computed results indicate that exit uniform flow is obtained with 1.19% of the maximal Mach-number deviation at the nozzle exit. The present design method achieves the continuously variable Mach-number flow during a wind tunnel running.展开更多
In order to improve structure performance of the dish solar concentrator,a three-dimensional model of dish solar concentrator was established based on the high-precision numerical algorithms.And a virtual wind tunnel ...In order to improve structure performance of the dish solar concentrator,a three-dimensional model of dish solar concentrator was established based on the high-precision numerical algorithms.And a virtual wind tunnel experiment with constant wind is adopted to investigate the pressure distribution of the reflective surface,velocity distribution of the fluid domain for the dish solar concentrator in different poses and wind speeds distribution.Some results about wind pressure distribution before and after dish solar concentrator surface and wind load velocity distribution in the entire fluid domain had been obtained.In particular,it is necessary to point out that the stiffness at the center of the dish solar concentrator should be relatively raised.The results can provide a theoretical basis for the improvement of solar concentrator dish structure as well as the failure analysis of dish solar concentrator in engineering practice.展开更多
Laminar-turbulent transition flow phenomena on a flat plate in a low-speed wind tunnel at different Reynolds numberswere studied numerically. The now calculation is based on an inviscid/boundary layer interaction meth...Laminar-turbulent transition flow phenomena on a flat plate in a low-speed wind tunnel at different Reynolds numberswere studied numerically. The now calculation is based on an inviscid/boundary layer interaction method with modifiedAbu-Ghannam/Shaw (AGS ) transihon criterion. The test sechon has non- symmetric al contoured walls, and the plate islocated biased the bottom side with a height ratio of 26: 14. In test case of steady flow, a laminar-turbulent transihontakes place and a small separation bubble occurs on the upper side of the plate, when the inlet Reynolds number is assmall as 0.63lx10-6. The predicted transihon location agrees well with that of the test results, but the separation bubbleis hardly to see from the calculatod velocity profiles though the printed data of velocity in this region do show thenegahve values. The further numerical Predictions with different Reynolds numbers corresponding to the incoming flowvelocities show that when the Reynolds number is greater than 1.379xl0-6, the separahon bubble does not occur, whichis coincident with the experimental results. The influence of the side wall geomeny on the transihon on the plate is alsostudied.展开更多
In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the c...In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the chord length.The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows.The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively.The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past.The results are as follows.The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel.And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.展开更多
基金Project(11072264)supported by the National Natural Science Foundation of China
文摘A design method was developed to specify the profile of the continuously variable Mach-number nozzle for the supersonic wind tunnel. The controllable contour design technique was applied to obtaining the original nozzle profile, while other Machnumbers were derived from the transformation of the original profile. A design scheme, covering a Mach-number range of3.0<Ma<4.0, was shown to illustrate the present design technique. To fully validate the present design method, computational fluid dynamics(CFD) analyses were carried out to study the flow quality in the test area of the nozzle. The computed results indicate that exit uniform flow is obtained with 1.19% of the maximal Mach-number deviation at the nozzle exit. The present design method achieves the continuously variable Mach-number flow during a wind tunnel running.
基金Projects(201208430262,201306130031)supported by the China Scholarship Council
文摘In order to improve structure performance of the dish solar concentrator,a three-dimensional model of dish solar concentrator was established based on the high-precision numerical algorithms.And a virtual wind tunnel experiment with constant wind is adopted to investigate the pressure distribution of the reflective surface,velocity distribution of the fluid domain for the dish solar concentrator in different poses and wind speeds distribution.Some results about wind pressure distribution before and after dish solar concentrator surface and wind load velocity distribution in the entire fluid domain had been obtained.In particular,it is necessary to point out that the stiffness at the center of the dish solar concentrator should be relatively raised.The results can provide a theoretical basis for the improvement of solar concentrator dish structure as well as the failure analysis of dish solar concentrator in engineering practice.
文摘Laminar-turbulent transition flow phenomena on a flat plate in a low-speed wind tunnel at different Reynolds numberswere studied numerically. The now calculation is based on an inviscid/boundary layer interaction method with modifiedAbu-Ghannam/Shaw (AGS ) transihon criterion. The test sechon has non- symmetric al contoured walls, and the plate islocated biased the bottom side with a height ratio of 26: 14. In test case of steady flow, a laminar-turbulent transihontakes place and a small separation bubble occurs on the upper side of the plate, when the inlet Reynolds number is assmall as 0.63lx10-6. The predicted transihon location agrees well with that of the test results, but the separation bubbleis hardly to see from the calculatod velocity profiles though the printed data of velocity in this region do show thenegahve values. The further numerical Predictions with different Reynolds numbers corresponding to the incoming flowvelocities show that when the Reynolds number is greater than 1.379xl0-6, the separahon bubble does not occur, whichis coincident with the experimental results. The influence of the side wall geomeny on the transihon on the plate is alsostudied.
文摘In the present study,numerical calculations of the flow-field around the airfoil model are performed by using the OpenFOAM in high subsonic flows.The airfoil model is NACA 64A010.The maximum thickness is 10 % of the chord length.The SonicFOAM and the RhoCentralFOAM are selected as the solver in high subsonic flows.The grid point is 158,000 and the Mach numbers are 0.277 and 0.569 respectively.The CFD data are compared with the experimental data performed by the cryogenic wind tunnel in the past.The results are as follows.The numerical results of the pressure coefficient distribution on the model surface calculated by the SonicFOAM solver showed good agreement with the experimental data measured by the cryogenic wind tunnel.And the data calculated by the SonicFOAM have the capability for the quantitative comparison of the experimental data at low angle of attack.
