Flow 2D

This is a modelling guide to help you get started simulating the effects a flow field and its influence on the propagation of an acoustic wave. This example will show you how to set up a 2D model of an ultrasonic flowmeter with a transmitter and receiver.

What is symbol?: Check out these articles to get more familiar with OnScale's scripting language symbol.

Model Description

Ultrasonic flowmeters use acoustic waves to determine the velocity of a fluid flowing in a pipe. At no flow conditions, frequencies of an ultrasonic wave transmitted into a pipe and its reflections from the fluid are the same. Under flowing conditions, the frequency of the reflected wave is different due to the doppler effect. When the fluid moves faster the frequency shift increases linearly. The transmitter processes signals from transmitted waves and its reflections to determine the flow rate.


Download and Open the Model

Download: Flow 2D

OnScale Input Files have the file extension *.flxinp. To open the downloaded file:

  1. Open OnScale 
  2. Select Analyst Mode
  3. Select the Menu button in the top left of the application
  4. Select Open

Preview Model


Preview model is used to view the geometry dimensions and material assignment of a model to ensure the script is correct. To preview a model, select the Preview Model icon in the Home tab of the application ribbon.


Note: Preview model will display data from any grph commands that come before the prcs command. If you have more than one grph command, you can cycle through the graphics by continuously selecting Preview Model. To close the preview, select Stop Preview.

Run Model on Cloud

To run the model on the cloud, select the Run on Cloud button in the Home tab of the application and follow these steps:

  1. Click Select and open the file you wish to run (Flow_2D.flxinp)
  2. Select Estimate
  3. Select Run

Download Results

  1. From the Home tab, select the Storage icon
  2. Select the Refresh icon to refresh storage
  3. Select the Job Name from the dropdown menu
  4. Select the Download button
  5. Select Download All

Choose a directory to download the results to. These results will be stored in the folder: 2D_Flow-YYYYMMDD-HHMMSS\1 where YYYYMMDD-HHMMSS is the current date and time.

Switch to Post Processor

Post Processor is a suite of tools used to visualize and analyse output data generated from OnScale simulations. Switch to Post Post Processor.


What kind of analysis can I do in Post Processor? Find out here.

Analyse Results

To see the beam profile of the phased array, follow these steps:

  1. In File Explorer, navigate to the download directory and double click the file '2D_Phased_Array.flxdato' to open it
  2. In Results Manager, double click the data array 'pmax' to plot it


What's Next?

Perform a parametric sweep using this model

Get more familiar with OnScale's 3 Modes and their capabilities