Experimental research of incipient turbulent flow frequency spectra in hydrodynamic unsteadiness

Abstract

Hydraulic and heat transfer processes play a very important role in the design and prototyping of aerospace technology. Unsteady conditions are the peculiarity of mostly aerospace systems. Flow acceleration and deceleration may significantly affect the heat transfer and hydrodynamic process in channels of aerospace systems. For unsteady process modeling, a fundamental research of unsteady hydrodynamic turbulent flow structure., Moscow Aviation Institute National Research University (MAI) has been building unsteady turbulent flow structures since 1989. An experimental facility was designed to provide gas flow acceleration and deceleration. Experimental data of a turbulent gas flow structure during flow acceleration and flow deceleration are presented. The frequency spectra of axial and radial velocity pulsations are based on experimental data. The results of experimental turbulent flow research demonstrate the fundamental hydrodynamic unsteadiness influence on the flow structure. The main results of the flow acceleration and deceleration experimental research show that there are tangible differences from the steady flow structure. The analysis of unsteady conditions influence on the turbulent pulsations generation and development mechanisms is presented. The results show the unsteady conditions influence onto turbulent vortexes disintegration tempo. The present paper describes a method of experimental research, methodology of data processing and turbulent accelerated and decelerated flow spectra results.