Experimental research of turbulent flow frequency spectra

Abstract

Hydraulic and heat transfer processes play a very important role in the design and prototyping of aerospace technology. In most cases this technique works under non-isothermal conditions. Non-isothermal conditions may significantly affect heat transfer and hydrodynamic process. Fundamental research of Non-isothermal turbulent flow is required for further engineering modeling. Models for unsteady processes calculation must be based on fundamental turbulent structure research. Moscow Aviation Institute National Research University (MAI) has been building non-isothermal turbulent flow structures since 1989. An experimental facility was designed to provide gas flow heating. Experimental data of a turbulent gas flow structure in isothermal and non-isothermal conditions are presented. The frequency spectra of axial and radial velocity pulsations are based on experimental data received. The results of experimental turbulent flow research demonstrate fundamental non-isothermal processes influence on the flow structure. The main results of non-isothermal experimental research show that there are three specific zones in turbulent flow structure: wall area, maximal turbulent structure transformation and flow core. The analysis of non-isothermal conditions influence on turbulent pulsations generation and development mechanisms is presented. The results show significant distinction in turbulent flow spectra between isothermal and non-isothermal conditions. The present paper describes a method of experimental research, methodology of data processing and non-isothermal turbulent flow spectra results.

Keywords

• turbulent flow structure
• non-isothermal flow
• frequency pulsations spectra