Abstract: The invention relates to a method for determining an indicator for a prediction of an instability in a compressor, which is designed as an axial or radial compressor, having the following steps: operating a compressor designed as an axial or radial compressor in operating states, which differ by different values of a characteristic parameter for a flow mass flux of the compressor, wherein the operating states are run through at decreasing flow mass fluxes; determining the values of the characteristic value for the flow mass flux for the operating states; detecting time-resolved pressure measurement values when running through the operating states by means of a pressure sensor, which is arranged in a housing of the compressor, upstream adjacent to an entrance plane of a rotor stage determining the skew for the operating states and determining an indicator for an instability of the compressor, if an algebraic sign change of the curve rise is determined for a curve profile of the skew over the characteristic par

Abstract: The invention relates to a boundary layer probe for determining a fluid flow, comprising a measuring surface which is formed on a probe wall and with which a fluid flow to be determined is in contact during a measuring operation. The boundary layer probe also comprises an assembly of measuring obstacles that are formed in the region of the measuring surface as obstacles which disrupt the fluid flow in a flow region adjacent to the measuring surface, each of which has an elongated obstacle course extending over a particular obstacle length, and which are arranged at substantially equidistant angular distances in the circumferential direction. The boundary layer probe additionally has pressure measuring points, each of which is radially adjacent to an associated obstacle in order to detect a local pressure in the region of the measuring surface. The invention additionally relates to a measuring assembly and to a method for determining a fluid flow. (FIG.

Abstract: The invention relates to a method for determining an indicator for a prediction of an instability in a compressor, which is designed as an axial or radial compressor, having the following steps: operating a compressor designed as an axial or radial compressor in operating states, which differ by different values of a characteristic parameter for a flow mass flux of the compressor, wherein the operating states are run through at decreasing flow mass fluxes; determining the values of the characteristic value for the flow mass flux for the operating states; detecting time-resolved pressure measurement values when running through the operating states by means of a pressure sensor, which is arranged in a housing of the compressor, upstream adjacent to an entrance plane of a rotor stage determining the skew for the operating states and determining an indicator for an instability of the compressor, if an algebraic sign change of the curve rise is determined for a curve profile of the skew over the characteristic par