Freebird 3D

Depth-Varying 3D Velocity Distribution

Velocity distribution in the depth direction is intuitively visualized using color-coded vectors: surface (red), mid-depth (blue), and bottom (green). Enables visualization of 3D flow over depressions and complex bed topography.

3D velocity vectors over a bed depression. Color-coded by depth: surface (red), mid-depth (blue), bottom (green)

Real River Application

Complex 3D flow conditions can be computed using detailed channel geometry obtained from multi-beam bathymetric surveys. Bed elevation contours and velocity vectors can be visualized on the iRIC GUI.

3D channel topography and computation results at Kamuikotan, Ishikari River, using multi-beam survey data (Asahikawa Development and Construction Department)

Hydraulic Jump Internal Structure Analysis

The non-hydrostatic model reproduces complex vortex structures inside hydraulic jumps occurring downstream of sills. Supports subcritical, supercritical, mixed, and hydraulic jump flows, enabling analysis that considers vertical acceleration beyond hydrostatic approximation.

3D velocity vectors of a hydraulic jump over a sill. Internal flow structure visualized by the non-hydrostatic model

3D Confluence/Bifurcation Computation

Supports multiple confluences and bifurcations with various patterns including right-angle confluence, right-angle bifurcation, and Y-junction. Real-time diversion ratio graph display is also available.

3D velocity vectors at a right-angle confluence (surface, mid-depth, bottom)

Right-angle bifurcation computation with diversion ratio graph (red: total, blue: main channel, green: distributary)

Density Current Simulation

Freebird's strongest capability. Can compute diverse density current patterns including lock exchange (stratification collapse), settling plumes, density currents between obstacles, and ring vortices. Applied to the Ishikari River salt wedge (seawater intrusion along the riverbed).

Four density current patterns: lock exchange, settling plume, density current between obstacles, and ring vortex

Salt wedge density current in the Ishikari River. Seawater intrusion along the riverbed visualized with 3D channel geometry

3D Turbulence Visualization

Complex vortices (Karman vortices, etc.) generated behind obstacles can be visualized in 3D using vorticity isosurfaces. Also supports general turbulence computation beyond density currents.

Isosurface visualization of turbulence structure crossing an obstacle

Complex Domain Computation with Obstacles

Computes 3D flow in complex domains with multiple obstacles and walls. Supports multiple inflow and outflow points.

3D velocity vectors in a complex domain with obstacle walls, multiple inflows and outflows