  In the application of high frequency acoustic flow measurement, viscothermal
dissipation and asymmetric acoustic modes cannot be overlooked. Present paper
mathematically formulates asymmetric linear disturbance dynamics in terms of
velocity and temperature disturbances based on the conservations of mass,
momentum and energy. An iterative calculation procedure, which is similar to
Galerkin method, is presented. Numerical analysis of asymmetric acoustic
features (phase velocity and attenuation coefficient) are comprehensively given
under the effects of viscothermal dissipation and shear flow convection. In the
end, flow measurement performance of asymmetric acoustic modes is literally
discussed. Numerical study shows that viscothermal dissipation affects the
cut-on frequency of acoustic modes and couples nonlinearly with shear
convection when the flow Mach number is large. These parameters impose
significant influences on measurement performance. Each acoustic mode has
inherent measurement derivation which can be theoretically used to compensate
the acoustic flow measurement error. Apparent prediction error may occur if the
viscothermal dissipation is taken out of consideration
