Accurate prediction of sonic boom is one of key challenges for the design of a low-boom supersonic aircraft. For most of available far-field prediction methods, the effect of atmospheric turbulence appearing in the pl...Accurate prediction of sonic boom is one of key challenges for the design of a low-boom supersonic aircraft. For most of available far-field prediction methods, the effect of atmospheric turbulence appearing in the planetary boundary layer cannot be considered, which results in remarkable inaccuracy of predicting ground-level sonic boom waveform. Although some efforts have been made to overcome the shortcoming, the turbulence effects are not yet well described so far. This article proposes an improved method by extending the two-dimensional Heterogeneous One-Way Approximation for the Resolution of Diffraction(HOWARD) equation to account for the axial and transverse convections of wind fluctuation as well as the effect of temperature fluctuation. The proposed method is validated by comparing the predictions with the flight-test data of JAXA D-SEND#1 LBM, which shows that the result of the proposed method is in better agreement with the flight-test data than that of the method without considering atmospheric turbulence effects.Then, distortion mechanism of sonic boom waveforms caused by atmospheric turbulence is analyzed by using the proposed method. It is indicated that the effect of turbulent convection makes uniform sonic-boom wavefronts irregular, which creates the condition of diffraction effect to perturb waveforms. Finally, the proposed method is applied to investigate the behavior of two types of waveforms given by the sonic boom minimization theory. Results show that a far-field waveform with a weaker initial shock is more beneficial for low-boom design of a supersonic aircraft.展开更多
After the last flight of the Concorde in 2003,sonic boom has been one of the obstacles to the return of a supersonic transport aircraft to service.To reduce the sonic boom intensity to an acceptable level,it is of gre...After the last flight of the Concorde in 2003,sonic boom has been one of the obstacles to the return of a supersonic transport aircraft to service.To reduce the sonic boom intensity to an acceptable level,it is of great significance to study the effect of lift distribution on far-field sonic boom,since lift is one of the most important contributors to an intense sonic boom.Existing studies on the longitudinal lift distribution used low-fidelity methods,such as Whitham theory,and in turn,only preliminary conclusions were obtained,such as that extending the lift distribution can reduce sonic boom.This paper uses a newly developed high-fidelity prediction method to quantitatively study the effect of longitudinal lift distribution on the sonic boom of a Canard-Wing-Stabilator-Body(CWSB)configuration.This high-fidelity prediction method combines near-feld CFD simulation with far-field propagation by solving the augmented Burgers equation.A multipole analysis method is employed for the extraction of near-field waveform in order to reduce computational cost.Seven configurations with the same total lift but different distributions are studied,and the quantitative relationship between the longitudinal lift distribution and far-field sonic boom intensity is investigated.It is observed that a small lift generated by the stabilator can prevent aft-stabilator and aft-fuselage shocks from merging,while the balanced lift generated by the canard and wing can effectively keep the corresponding shocks further apart,which is beneficial for reducing both the on-track and off-track sonic boom.In turn,the acoustic level perceived at the ground can be reduced by 5.9 PLdB on-track and 5.4 PLdB off-track,on average.展开更多
Despite over fifty years of research on shock wave boundary layer effects and interactions,many related technical issues continue to be controversial and debated.The present survey provides an overview of the present ...Despite over fifty years of research on shock wave boundary layer effects and interactions,many related technical issues continue to be controversial and debated.The present survey provides an overview of the present state of knowledge on such effects and interactions,including discussions of:(i)general features of shock wave interactions,(ii)test section configurations for investigation of shock wave boundary layer interactions,(iii)origins and sources of unsteadiness associated with the interaction region,(iv)interactions which included thermal transport and convective heat transfer,and(v)shock wave interaction control investigations.Of particular interest are origins and sources of low-frequency,large-scale shock wave unsteadiness,flow physics of shock wave boundary layer interactions,and overall structure of different types of interactions.Information is also provided in regard to shock wave investigations,where heat transfer and thermal transport were important.Also considered are investigations of shock wave interaction control strategies,which overall,indicate that no single shock wave control strategy is available,which may be successfully applied to different shock wave arrangements,over a wide range of Mach numbers.Overall,the survey highlights the need for additional understanding of fundamental transport mechanisms,as related to shock waves,which are applicable to turbomachinery,aerospace,and aeronautical academic disciplines.展开更多
The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout ...The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout of route aircraft and also peculiarities of some prospective flight vehicles.Also there are some hypersonic vehicles aerodynamics questions examined along with problems of creation of civil supersonic transport aircraft.There is a description given for well-known and some newer methods of flow control for drag reduction.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U20B2007,11972305)the Aeronautical Science Foundation of China(No.2019ZA053004)+1 种基金the Shaanxi Science Fund for Distinguished Young Scholars(No.2020JC-13)the“111”Project of China(No.B17037)。
文摘Accurate prediction of sonic boom is one of key challenges for the design of a low-boom supersonic aircraft. For most of available far-field prediction methods, the effect of atmospheric turbulence appearing in the planetary boundary layer cannot be considered, which results in remarkable inaccuracy of predicting ground-level sonic boom waveform. Although some efforts have been made to overcome the shortcoming, the turbulence effects are not yet well described so far. This article proposes an improved method by extending the two-dimensional Heterogeneous One-Way Approximation for the Resolution of Diffraction(HOWARD) equation to account for the axial and transverse convections of wind fluctuation as well as the effect of temperature fluctuation. The proposed method is validated by comparing the predictions with the flight-test data of JAXA D-SEND#1 LBM, which shows that the result of the proposed method is in better agreement with the flight-test data than that of the method without considering atmospheric turbulence effects.Then, distortion mechanism of sonic boom waveforms caused by atmospheric turbulence is analyzed by using the proposed method. It is indicated that the effect of turbulent convection makes uniform sonic-boom wavefronts irregular, which creates the condition of diffraction effect to perturb waveforms. Finally, the proposed method is applied to investigate the behavior of two types of waveforms given by the sonic boom minimization theory. Results show that a far-field waveform with a weaker initial shock is more beneficial for low-boom design of a supersonic aircraft.
基金sponsored by the National Natural Science Foundation of China(Nos.12072285,U20B2007)the Shaanxi Science Fund for Distinguished Young Scholars,China(No.2020JC-13)the Natural Science Funding of Shaanxi Province,China(No.2020JM-127).
文摘After the last flight of the Concorde in 2003,sonic boom has been one of the obstacles to the return of a supersonic transport aircraft to service.To reduce the sonic boom intensity to an acceptable level,it is of great significance to study the effect of lift distribution on far-field sonic boom,since lift is one of the most important contributors to an intense sonic boom.Existing studies on the longitudinal lift distribution used low-fidelity methods,such as Whitham theory,and in turn,only preliminary conclusions were obtained,such as that extending the lift distribution can reduce sonic boom.This paper uses a newly developed high-fidelity prediction method to quantitatively study the effect of longitudinal lift distribution on the sonic boom of a Canard-Wing-Stabilator-Body(CWSB)configuration.This high-fidelity prediction method combines near-feld CFD simulation with far-field propagation by solving the augmented Burgers equation.A multipole analysis method is employed for the extraction of near-field waveform in order to reduce computational cost.Seven configurations with the same total lift but different distributions are studied,and the quantitative relationship between the longitudinal lift distribution and far-field sonic boom intensity is investigated.It is observed that a small lift generated by the stabilator can prevent aft-stabilator and aft-fuselage shocks from merging,while the balanced lift generated by the canard and wing can effectively keep the corresponding shocks further apart,which is beneficial for reducing both the on-track and off-track sonic boom.In turn,the acoustic level perceived at the ground can be reduced by 5.9 PLdB on-track and 5.4 PLdB off-track,on average.
文摘Despite over fifty years of research on shock wave boundary layer effects and interactions,many related technical issues continue to be controversial and debated.The present survey provides an overview of the present state of knowledge on such effects and interactions,including discussions of:(i)general features of shock wave interactions,(ii)test section configurations for investigation of shock wave boundary layer interactions,(iii)origins and sources of unsteadiness associated with the interaction region,(iv)interactions which included thermal transport and convective heat transfer,and(v)shock wave interaction control investigations.Of particular interest are origins and sources of low-frequency,large-scale shock wave unsteadiness,flow physics of shock wave boundary layer interactions,and overall structure of different types of interactions.Information is also provided in regard to shock wave investigations,where heat transfer and thermal transport were important.Also considered are investigations of shock wave interaction control strategies,which overall,indicate that no single shock wave control strategy is available,which may be successfully applied to different shock wave arrangements,over a wide range of Mach numbers.Overall,the survey highlights the need for additional understanding of fundamental transport mechanisms,as related to shock waves,which are applicable to turbomachinery,aerospace,and aeronautical academic disciplines.
文摘The article represents the discussion of several separate directions of investigations,which are performed by TsAGI flight vehicles aerodynamics specialists at the time.There are some major trends of classical layout of route aircraft and also peculiarities of some prospective flight vehicles.Also there are some hypersonic vehicles aerodynamics questions examined along with problems of creation of civil supersonic transport aircraft.There is a description given for well-known and some newer methods of flow control for drag reduction.
