We perform numerical simulations to investigate the stellar wind from interacting binary stars .
Our aim is to find analytical formulae describing the outflow structure .
In each binary system the more massive star is in the asymptotic giant branch and its wind is driven by a combination of pulsations in the stellar surface layers and radiation pressure on dust , while the less massive star is in the main sequence .
Time averages of density and outflow velocity of the stellar wind are calculated and plotted as profiles against distance from the centre of mass and colatitude angle .
We find that mass is lost mainly through the outer Lagrangian point L _ { 2 } .
The resultant outflow develops into a spiral at low distances from the binary .
The outflowing spiral is quickly smoothed out by shocks and becomes an excretion disk at larger distances .
This leads to the formation of an outflow structure with an equatorial density excess , which is greater in binaries with smaller orbital separation .
The pole-to-equator density ratio reaches a maximum value of \sim 10 ^ { 5 } at Roche-Lobe Overflow state .
We also find that the gas stream leaving L _ { 2 } does not form a circumbinary ring for stellar mass ratios above 0.78 , when radiation pressure on dust is taken into account .
Analytical formulae are obtained by curve fitting the 2-dimensional , azimuthally averaged density and outflow velocity profiles .
The formulae can be used in future studies to setup the initial outflow structure in hydrodynamic simulations of common-envelope evolution and formation of planetary nebulae .