diff --git a/examples/ZeldovichPancake_3D/plotSolution.py b/examples/ZeldovichPancake_3D/plotSolution.py
index 2a175e346e041a142c6921052ccf13978afa8a38..b7e8fd93813e8906055262ed6deba9a40ec3d0a6 100644
--- a/examples/ZeldovichPancake_3D/plotSolution.py
+++ b/examples/ZeldovichPancake_3D/plotSolution.py
@@ -69,6 +69,7 @@ scheme = sim["/HydroScheme"].attrs["Scheme"]
kernel = sim["/HydroScheme"].attrs["Kernel function"]
neighbours = sim["/HydroScheme"].attrs["Kernel target N_ngb"]
eta = sim["/HydroScheme"].attrs["Kernel eta"]
+alpha = sim["/HydroScheme"].attrs["Alpha viscosity"]
git = sim["Code"].attrs["Git Revision"]
# Cosmological parameters
@@ -178,8 +179,8 @@ ylabel("${\\rm{Temperature}}~T$", labelpad=0)
# Information -------------------------------------
subplot(236, frameon=False)
-text(-0.49, 0.9, "Zeldovich pancake with $\\gamma=%.3f$ in 1D at $t=%.2f$"%(gas_gamma,time), fontsize=10)
-text(-0.49, 0.8, "$z={0:.2f}$".format(redshift))
+text(-0.49, 0.9, "Zeldovich pancake at z=%.2f "%(redshift), fontsize=10)
+text(-0.49, 0.8, "adiabatic index $\\gamma=%.2f$, viscosity $\\alpha=%.2f$"%(gas_gamma, alpha), fontsize=10)
plot([-0.49, 0.1], [0.62, 0.62], 'k-', lw=1)
text(-0.49, 0.5, "$\\textsc{Swift}$ %s"%git, fontsize=10)
text(-0.49, 0.4, scheme, fontsize=10)
diff --git a/examples/ZeldovichPancake_3D/zeldovichPancake.yml b/examples/ZeldovichPancake_3D/zeldovichPancake.yml
index 5cfa01ff954a959e06076035ae22240bb3c5a120..4d83d805cfebb837f37058167a4e3c974a936317 100644
--- a/examples/ZeldovichPancake_3D/zeldovichPancake.yml
+++ b/examples/ZeldovichPancake_3D/zeldovichPancake.yml
@@ -24,7 +24,8 @@ Snapshots:
basename: zeldovichPancake # Common part of the name of output files
time_first: 0. # Time of the first output (in internal units)
delta_time: 1.04 # Time difference between consecutive outputs (in internal units)
- scale_factor_first: 0.00991
+ scale_factor_first: 0.00991
+ compression: 4
# Parameters governing the conserved quantities statistics
Statistics:
diff --git a/src/hydro/Minimal/hydro.h b/src/hydro/Minimal/hydro.h
index 01abe55e7267ca04a7f3e9740c10c681f86f29ea..1f6407cfbf5dbe028db290b8a5de42a8efc40ed0 100644
--- a/src/hydro/Minimal/hydro.h
+++ b/src/hydro/Minimal/hydro.h
@@ -570,6 +570,12 @@ __attribute__((always_inline)) INLINE static void hydro_convert_quantities(
struct part *restrict p, struct xpart *restrict xp,
const struct cosmology *cosmo) {
+ /* Convert the physcial internal energy to the comoving one. */
+ /* u' = a^(3(g-1)) u */
+ const float factor = 1.f / cosmo->a_factor_internal_energy;
+ p->u *= factor;
+ xp->u_full *= factor;
+
/* Compute the pressure */
const float pressure = gas_pressure_from_internal_energy(p->rho, p->u);
diff --git a/src/hydro/Minimal/hydro_iact.h b/src/hydro/Minimal/hydro_iact.h
index 42fd93d6062cbfcea5cf5297eeda0bb6525f3cad..0193886f57413540d110c513ae3119ba1315f384 100644
--- a/src/hydro/Minimal/hydro_iact.h
+++ b/src/hydro/Minimal/hydro_iact.h
@@ -172,10 +172,13 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
/* Compute dv dot r. */
const float dvdr = (pi->v[0] - pj->v[0]) * dx[0] +
(pi->v[1] - pj->v[1]) * dx[1] +
- (pi->v[2] - pj->v[2]) * dx[2] + a2_Hubble * r2;
+ (pi->v[2] - pj->v[2]) * dx[2];
+
+ /* Add Hubble flow */
+ const float dvdr_Hubble = dvdr + a2_Hubble * r2;
/* Are the particles moving towards each others ? */
- const float omega_ij = min(dvdr, 0.f);
+ const float omega_ij = min(dvdr_Hubble, 0.f);
const float mu_ij = fac_mu * r_inv * omega_ij; /* This is 0 or negative */
/* Compute sound speeds and signal velocity */
@@ -285,10 +288,13 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
/* Compute dv dot r. */
const float dvdr = (pi->v[0] - pj->v[0]) * dx[0] +
(pi->v[1] - pj->v[1]) * dx[1] +
- (pi->v[2] - pj->v[2]) * dx[2] + a2_Hubble * r2;
+ (pi->v[2] - pj->v[2]) * dx[2];
+
+ /* Add Hubble flow */
+ const float dvdr_Hubble = dvdr + a2_Hubble * r2;
/* Are the particles moving towards each others ? */
- const float omega_ij = min(dvdr, 0.f);
+ const float omega_ij = min(dvdr_Hubble, 0.f);
const float mu_ij = fac_mu * r_inv * omega_ij; /* This is 0 or negative */
/* Compute sound speeds and signal velocity */
diff --git a/src/hydro_properties.c b/src/hydro_properties.c
index 9520781be45f7d9b59534c57e542e0802759aaec..65d009dd39556d9f9ff25c2c4a6d2092a0a58099 100644
--- a/src/hydro_properties.c
+++ b/src/hydro_properties.c
@@ -215,6 +215,7 @@ void hydro_props_print_snapshot(hid_t h_grpsph, const struct hydro_props *p) {
p->initial_internal_energy);
io_write_attribute_f(h_grpsph, "Hydrogen mass fraction",
p->hydrogen_mass_fraction);
+ io_write_attribute_f(h_grpsph, "Alpha viscosity", const_viscosity_alpha);
}
#endif
diff --git a/theory/Cosmology/coordinates.tex b/theory/Cosmology/coordinates.tex
index 38a571aefea68fbe1bc7a8ebc3867109f1c4736e..a1dbff71c13cbd62acde83c14e9e81f0fbc41214 100644
--- a/theory/Cosmology/coordinates.tex
+++ b/theory/Cosmology/coordinates.tex
@@ -88,13 +88,13 @@ gravitational terms. SPH flavours that evolve the internal energy $u$ instead of
entropy require the additional equation of motion describing the evolution of
$u'$:
\begin{equation}
- \dot{u}_i' = \frac{P_i'}{\rho_i'^2}\left[3H\rho_i' + \frac{1}{a^2}f_i'\sum_jm_j\left(\mathbf{v}_i' -
- \mathbf{v}_j'\right)\cdot\mathbf{\nabla}_i'W_{ij}'(h_i)\right],
+ \dot{u}_i' = \frac{1}{a^2}\frac{P_i'}{\rho_i'^2} f_i'\sum_jm_j\left(\mathbf{v}_i' -
+ \mathbf{v}_j'\right)\cdot\mathbf{\nabla}_i'W_{ij}'(h_i).
\label{eq:cosmo_eom_u}
\end{equation}
-where the first term in the brackets accounts for the change in energy
-due to the expansion of the Universe. The scale-factors appearing in
-the equations are later absorbed in the time-integration operators
+
+In all these cases, the scale-factors appearing in the equations are
+later absorbed in the time-integration operators
(Sec.~\ref{ssec:operators}) such that the RHS of the equations of
motions is identical for the primed quantities to the ones obtained in
the non-cosmological case for the physical quantities.