  We present a variant of the immersed boundary method integrated with octree
meshes for highly efficient and accurate Large-Eddy Simulations (LES) of flows
around complex geometries. We demonstrate the scalability of the proposed
method up to $\mathcal{O}(32K)$ processors. This is achieved by (a) rapid
in-out tests; (b) adaptive quadrature for an accurate evaluation of forces; (c)
tensorized evaluation during matrix assembly. We showcase this method on two
non-trivial applications: accurately computing the drag coefficient of a sphere
across Reynolds numbers $1-10^6$ encompassing the drag crisis regime;
simulating flow features across a semi-truck for investigating the effect of
platooning on efficiency.
