the CSFs, and those escaping the acceleration site, depend on the shock velocities, the number densities, and the magnetic fields in the flows. We show below that sub-PeV and PeV neutrinos from colliding shocks in galactic and extragalactic compact clusters of young stars with reasonable parameters, such as those expected in the  compact cluster, can explain a fraction of the IceCube neutrino events.

![Colliding flow geometry where the stellar wind (left) was approximated from the analytic model of [@wilkin96], while the SNR shock was assumed to be spherical. The star, or cluster center, approaches the SN explosion center with speed $V_0$. The spectrum of the Fermi accelerated CRs was derived taking into account effects of the flow velocity projection on the curved shock surfaces. []{data-label="fig:3D"}](f1.pdf){width="3.4in"}

Particle acceleration in colliding shock flows {#sec:CSF}
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In order to model the proton acceleration in a compact stellar cluster, we used the [nonlinear]{}, time-dependent model of CSFs presented in @MNRAS_BGO13. The main modification is that here we allow for different parameters for the wind termination shock and the SNR blast wave. We have also introduced an approximation to account for the shape of the shock (as illustrated in Fig. \[fig:3D\]) using an analytic expression 