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Hydrodynamic Bearing Software


RAPPID™ hydrodynamic bearing analysis software utilizes the full Navier-Stokes solution and offers the following capabilities:

  • Laminar, transitional and turbulent flow
  • Full thermal model
  • Results include full effects of fluid inertia and shear
  • Axial and/or circumferential grooves for sleeve bearings
  • Geometrically correct pivot models for tilting pad bearings

Why Navier-Stokes for bearing rotordynamic coefficients? Download or Open


RAPPID™ hydrodynamic bearing analysis software has a wide array of features are available to enable physically realistic modeling of hydrodynamic bearings, including:

  • Ability to solve for load given eccentricity and attitude angle or vice versa
  • Hot fluid carry over model
  • Thermal model includes convection to shaft and housing, and conduction through housing
  • Housing thermal model allows for two dissimilar materials (i.e., babbitt and steel, etc.)
  • Automatic grid generation
  • Automated initial guess algorithm when given load and iterating on the journal's position
  • Groove model accounting for pressure effect of flow preswirl
  • Separate models for the three common pivot types: pin, rocker, and ball/socket
  • Pivot models include friction, radial stiffness, pad inertia, and pivot curvature effects
  • Full modeling of pressure drop across sleeve bearings
  • Solution method solves fully coupled momentum, continuity, and energy equations
  • Contains library of oil properties for popular ISO grades

Analysis Results

RAPPID™ hydrodynamic bearing analysis software yields results needed for a comprehensive assessment of bearing performance, including:

  • Dynamic Results: Stiffness, damping, and mass coefficients and whirl frequency ratio
  • Optional frequency dependent rotordynanmic characteristics
  • Eccentricity, attitude angle, pad orientation, flow rate, power loss
  • Peak film pressure, peak pad temperature, and peak fluid temperature
  • Inlet temperature, temperature rise, maximum temperature, minimum film thickness
  • Max circumferential Reynolds number and flow condition (laminar, transitional, or turbulent)

Bearing Configurations

RAPPID™ hydrodynamic bearing analysis software can analyze most conventional bearing configurations and many advanced configurations, including:

  • Pin, rocker, and ball/socket tilt pad hydrodynamic journal and thrust
  • Radially fed sleeve, lobe, partial arc, pressure dam And tapered land journal
  • Axially fed sleeve and lobe journal
  • Floating ring sleeve journal
  • Multileaf bending foil journal