Ivan Nepomnyashchikh

9 Questions 27 Answers 0 Followers

Questions related from Ivan Nepomnyashchikh

Is there anything faster than Xarray or Pandas out there?

Hello, dear RG community. Personally, I have found Xarray to be excruciatingly slow, especially for big datasets and nonstandard operations (like a custom filtering function). The only suggestion...

16 July 2024 4,839 2 View

How to derive the volume based equation for gas fraction starting from Dr. Ishii's definition of local gas fraction?

Hello, dear RG community. Very often, gas fraction (also known as void fraction or gas holdup) is thought of as a ratio of the gas volume to the total volume:...

05 April 2024 7,342 0 View

How to prevent lumping of fluorescent polystyrene PIV particles in water?

Hello dear RG community. I'm doing PIV in water with red fluorescent 8 micron polystyrene PIV particles (Fischer catalog number 36-3B https://www.thermofisher.com/order/catalog/product/36-3B). I...

27 January 2023 6,972 2 View

How to mitigate camera's error resulting in a nonuniformly lit and less bright first image in a PIV pair of images?

Hello dear RG community. I have a Dantec PIV setup consisting of, in particular, an iNanoSense camera and a SoloPIV 120 NewWave Research laser. I'm getting the first image less bright and...

02 January 2023 2,229 6 View

Is there a good algorithm for bubble identification for a wider range of two-phase flow regimes?

Hello dear RG community. I'm trying to identify contours of bubbles on the images taken with Nikon 1 J4 camera ( backlit through a diffuser with a halogen lamp). I use Python. I'm trying to go...

17 November 2022 4,620 1 View

How to calculate uncertainty of signal acquisition with NI USB-6009 DAQ board?

Hello dear RG community. I'm acquiring signal from pressure transducers and a turbine flow meter with NI USB-6009 DAQ board. I'm not sure how calculate the accuracy of the DAQ board. I've been...

10 November 2022 979 1 View

How to extract data from only one time step generated in OpenFOAM?

Hello dear RG community. I ran a transient case in OpenFOAM. I got a lot of subfolders for each time step. Then I type paraFoam and it loads all the time steps. It takes about 20 minutes to load...

28 September 2021 5,751 5 View

Is there an open source software to run a laser for particle image velocimetry?

Hello dear RG community. I'm wondering if there is an open source software to run a PIV laser. I know about OpenPIV, but that thing only post-processes the images. I can't wrap my head around...

24 September 2021 5,337 10 View

Specs for Action sensor pressure transducer?

Hello dear RG community. I'm wondering if anybody has specifications for Action sensor pressure transducer, 0-100psig, MODEL ASP-420, SERIAL NUMBER SE-1460. Thank you in advance. Ivan

24 June 2021 196 0 View