DNS visualisations

This repository contains movies of Direct Numerical Simulations (DNS) showing two-dimensional nonlinear forcing and three-dimensional breakdown to turbulence in a heated flat-plate boundary layer with a fluid at supercritical pressure. The movies are part of the publication:

https://arxiv.org/abs/2506.06703

---

Explanation

Movie #1: Two-dimensional simulation — nonlinear forcing under pseudo-boiling conditions

This movie (Figure 9 in the manuscript) illustrates contours of density (ρ) in an xy-plane over one forcing period (T₀, the period of the fundamental wave). The pseudo-critical point at y = y_pc lies within the green region, i.e., between 98% of max(c_p) and max(c_p).

▶️ View movie1.mp4

---

Movies #2, #3, and #4: Three-dimensional simulations — breakdown to turbulence

These movies (Figure 12 in the manuscript) show isosurfaces of the Q-criterion, colored by streamwise velocity magnitude, over one forcing period (T₀). The side xy-plane displays instantaneous spanwise vorticity (ω_z). Separation zones (regions with u < 0) are shown as cyan isosurfaces in cases Tw110-LA and Tw110-IA. For clarity, the domain is repeated three times in the spanwise direction.

• Movie #2: Case Tw095-LA — Subcritical regime (Q = 0.015)
  
  ▶️ View movie2.mp4

• Movie #3: Case Tw110-LA — Transcritical regime with finite-amplitude oblique wave (Q = 0.020)
  
  ▶️ View movie3.mp4

• Movie #4: Case Tw110-IA — Transcritical regime with infinitesimal-amplitude oblique wave (Q = 0.020)
  
  ▶️ View movie4.mp4