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README.md

IssyOsborne

IssyOsborne: transIent Squeeze and Starvation in elastohYdrodynamic - OScillating luBricated contact sOlving Reynolds oNe-dimensional Equation

This name is a tribute to the famous physicist Osborne Reynolds pioneer in the understanding of fluid dynamics.

Important: This software requires Igor v. 8.0 to run.

Installation

Clone the git repository and open the IssyOsborne.pxp in Igor Pro (Use the demo version of Igor Pro to try IssyOsborne).

Using IssyOsborne

1/ In the "Input profile" tab, set the ball radius, load, material moduli, fluid viscosity and piezoviscosity values.

2/ Input initial profile

h(x,0)
(two methods):

  • Method 1: Use the film thickness experimental data measured during a classical constant velocity test (horseshoe shape profile). The set velocity should correspond to the velocity amplitude of the periodical velocity set in the "Main settings" tab. Just past

    (h, X)
    data in the table. Uncheck "Auto. calculated initial profile" box.

  • Method 2: Press "Calculation button" and let IssyOsborne calculate an initial profile based on Crook's approximation, Moes-Venner equation of central film thickness

    h(0,0)
    and a realistic smooth profile with an estimate of the minimum film thickness
    h(x_m,0)
    .

The number of points and smoothness characteristics of the profile can be adjusted using the inputs "Size", "Interval" and "Smooth profile". Inputs panel\label{fig:2}

3/ In the "main settings tab":

  • Set the contact kinematics either by setting the velocity amplitude
    ^*
    and the acceleration/deceleration time or by setting the sliding frequency and the stroke (i.e., twice the displacement amplitude).
  • Set the desired number of the displayed decelerations/accelerations.
  • The time step (i.e., graph resolution) is automatically optimized. This parameter can be manually adjusted for a better graphical resolution implying a longer calculation time.
  • Press "Start button" to launch the algorithm and display the results.
  • Optionally, the curve range can be adjusted to focus on some parts of deceleration or acceleration sequences.
  • Check "Auto. calculated initial profile box" to automatically calculate the initial profile while changing "Main settings" parameters. Results panel\label{fig:1}

^*
The algorithm uses a triangular velocity as first approximation of the sine kinematics.

Results display

The "input profile" tab displays:

  • The initial profile
    h(X,0)
    associated to its data table
    (h,X)
    .
  • The central film thickness
    h(0,0)
    .
  • The minimum film thickness
    h(X_m,0)
    .
  • The Hertzian contact radius.
  • The dimensionless Hersey number calculated by the formula
    N_{\mathrm{H}}=\frac{\eta_0\cdot f}{P}
    or
    N_{\mathrm{H}}=\frac{\eta_0\cdot \dot X}{P\cdot R_\mathrm{a}}
    if the surfaces combined roughness
    R^*_{\mathrm{a}}
    is specified.
  • The transition Hersey number (that will be better explained in our next publication in 2023).

The "Main settings" tab displays:

  • The velocity evolution
    u(t)
    .
  • The colored profiles with time
    h(X,t)
    .
  • The central profile evolution
    h(0,t)
    .
  • The colored profile waterfall with film thickness
    h(X,t)
    .

Community Guidelines

Bug reports and requests for improvements, and new features are welcomed! Please feel free to make a post to Issue Tracker or contact Dr. Malik Yahiaoui, malik.yahiaoui@enit.fr

License

GPLv3 or later