A simple model for homogeneous-heterogeneous reactions in stagnation-point boundary-layer flow is constructed in which the homogeneous (bulk) reaction is assumed to be given by isothermal cubic autocatalator kinetics and the heterogeneous (surface) reaction by first order kinetics. The possible steady states of this system are analysed in detail in the case when the diffusion coefficients of both reactant and autocatalyst are equal. Hysteresis bifurcations leading to multiple solutions are found. The temporal stability of these steady states is then discussed.

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A simple model for homogeneous-heterogeneous reactions in stagnation-point boundary-layer flow, derived in a previous paper, is discussed in the case when the diffusion coefficients of the reactant and autocatalyst are different, characterized by the dimensionless parameter ft. The steady states of this system show the possibility of multiple solution branches through hysteresis bifurcations, the details of which are examined. Solutions valid for large and small of fi are obtained, and it is shown that, for large 6, it is the surface reaction which is the dominant effect, whereas for small values of 6, the homogeneous reaction becomes the most important mechanism.

The free convection boundary-layer flow near a stagnation point driven by catalytic surface heating is considered. The case without fuel consumption is treated first, and it is shown that the steady state equations admit multiple solutions. Explicit expressions can be obtained for these solution branches and it is found that a hysteresis point occurs when the activation energy parameter e = 1/5. The effect of fuel consumption is seen to be characterised by the dimensionless parameter a and numerical results are obtained for a range of values of a and E, as well as Prandtl number or and Schmidt number S c . Multiple solutions are again observed and analytic expressions for the bifurcation points can be found when a-= S c . For o-# Sc these have to be determined numerically.

The effects that blowing and suction have on the free convection boundary layer on a vertical surface with a given surface heat flux are considered. Similarity equations are derived first, their solution being dependent on the wall flux exponent n and a dimensionless transpiration parameter y, (as well as on the Prandtl number). The range of existence of solutions is considered, with it being shown that solutions exist only for n > -1 for blowing, whereas they exist for all n > n o for suction, where n o < -1 and depends on y. The solutions for strong suction and blowing are derived. In the latter case the asymptotic structure is found to be different for n in the three ranges -1 < n < -, -< n < , n > -. Results are then obtained for the non-similarity problem of constant heat flux with a constant transpiration velocity. Solutions valid for large distances from the leading edge for both suction and blowing are derived.