profile should tend to a power law, where $S_\rmn{e}(r) \propto r^{1.1}$ [e.g. @Tozzi:2001; @Kay:2004a; @Voit:2005; @Mitchell:2009]. X-ray observations to date are consistent with this predicted behaviour [see e.g. @Ponman:2003; @Piffaretti:2005; @Donahue:2006; @Pratt:2006; @Morandi:2007; @Zhang:2008; @Pratt:2010], and a recent study of the high resolution *Chandra* Data Archive by [@Cavagnolo:2009] has provided evidence of this expected behaviour in a collection of 239 clusters. Therefore, for the purposes of providing a physically motivated gas model, we choose the beta-model-like parametrization for the entropy profile $$S_\rmn{e}(r) = S_\rmn{e0}\left(1 + \left(r\over
r_{\rmn{core}}\right)^2\right)^{\alpha},$$ where $S_\rmn{e0}$ is the central entropy value, $r_{\rmn{core}}$ is a scale radius, and $\alpha$ is a parameter describing the behaviour at radii much larger than $r_\rmn{core}$. In terms of the central electron density and temperature, $S_\rmn{e0} =
T_\rmn{e0}/n_{\rmn{e}0}^{2/3}$. Given the findings of the simulation and observational work outlined above, one would expect the entropy profile to be dominated by non-gravitational processes at radii smaller than $r_\rmn{core} \sim 0.1r_{200}$, and at larger radii follow a power-law $S_\rmn{e} \propto r^{2\alpha}$, where $\alpha \sim
0.55$.

We note that recent X-ray observations of the ICM using *Suzaku* give evidence for a deviation in the entropy behaviour from the $r^{1.1}$ power-law to flatter profiles at large radii [e.g. 