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
Unsteady flow characteristics of a normal shock wave,a lambda foot,and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow.The supersonic wind tunnel facility,...Unsteady flow characteristics of a normal shock wave,a lambda foot,and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow.The supersonic wind tunnel facility,containing this test section,provides a Mach number of approximately 1.54 at the test section entrance.Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section.These data are analyzed to determine shock wave unsteadiness characteristics,including grayscale spectral energy variations with frequency,as well as time and space correlations,which give coherence and time lag properties associated with perturbations associated with different flow regions.Results illustrate the complexity and unsteadiness of shock-wave-boundary-layerinteractions,including event frequencies from grayscale spectral energy distributions determined using a Lagrangian approach applied to shock wave location,and by grayscale spectral energy distributions determined using ensemble-averaging applied to multiple closely-located stationary pixel locations.Auto-correlation function results and two-point correlation functions(in the form of magnitude squared coherence)quantify the time-scales of periodic events,as well as the coherence of flow perturbations associated with different locations,over a range of frequencies.Associated time lag data provide information on the originating location of perturbation events,as well as the propagation direction and event sequence associated with different flow locations.Additional insight into spatial variations of time lag and flow coherence is provided by application of magnitude squared coherence analysis to multiple locations,relative to a single location associated with the normal shock wave.展开更多
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.
基金The Alabama Innovation Fund(Contract ID No.61070000002)the University of Alabama Endowment Fund,and the Office of the Vice President for Research and Economic Development of the University of Alabama in Huntsville are acknowledged for financial support for the research which is reported within the present paper.
文摘Unsteady flow characteristics of a normal shock wave,a lambda foot,and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow.The supersonic wind tunnel facility,containing this test section,provides a Mach number of approximately 1.54 at the test section entrance.Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section.These data are analyzed to determine shock wave unsteadiness characteristics,including grayscale spectral energy variations with frequency,as well as time and space correlations,which give coherence and time lag properties associated with perturbations associated with different flow regions.Results illustrate the complexity and unsteadiness of shock-wave-boundary-layerinteractions,including event frequencies from grayscale spectral energy distributions determined using a Lagrangian approach applied to shock wave location,and by grayscale spectral energy distributions determined using ensemble-averaging applied to multiple closely-located stationary pixel locations.Auto-correlation function results and two-point correlation functions(in the form of magnitude squared coherence)quantify the time-scales of periodic events,as well as the coherence of flow perturbations associated with different locations,over a range of frequencies.Associated time lag data provide information on the originating location of perturbation events,as well as the propagation direction and event sequence associated with different flow locations.Additional insight into spatial variations of time lag and flow coherence is provided by application of magnitude squared coherence analysis to multiple locations,relative to a single location associated with the normal shock wave.
