diff --git a/src/lagrangian/turbulence/submodels/Thermodynamic/ParticleForces/BrownianMotion/BrownianMotionForce.C b/src/lagrangian/turbulence/submodels/Thermodynamic/ParticleForces/BrownianMotion/BrownianMotionForce.C
index 9dffc11bcd..3903093628 100644
--- a/src/lagrangian/turbulence/submodels/Thermodynamic/ParticleForces/BrownianMotion/BrownianMotionForce.C
+++ b/src/lagrangian/turbulence/submodels/Thermodynamic/ParticleForces/BrownianMotion/BrownianMotionForce.C
@@ -187,9 +187,8 @@ Foam::forceSuSp Foam::BrownianMotionForce<CloudType>::calcCoupled
     }
     else
     {
-        const scalar rhoRatio = p.rho()/p.rhoc();
         const scalar s0 =
-            216*muc*sigma*Tc/(sqr(mathematical::pi)*pow5(dp)*(rhoRatio)*cc);
+            216*muc*sigma*Tc/(sqr(mathematical::pi)*pow5(dp)*sqr(p.rho())*cc);
         f = eta*sqrt(mathematical::pi*s0/dt);
     }