Paper Number
TM12 My Program
Session
Techniques and Methods: Rheometry, Tribometry, Spectroscopy and Microscopy
Title
Marsh funnel protorheology for yield stress fluids - operational limits and design insights
Presentation Date and Time
October 22, 2025 (Wednesday) 11:30
Track / Room
Track 7 / Sweeney Ballroom D
Authors
- Gupta, Shatakshi (UNIVERSITY OF ILLINOIS AT URBANA - CHAMPAIGN, Mechanical Science and Engineering)
- Ewoldt, Randy H. (University Of Illinois Urbana-champaign, Mechanical Science and Engineering)
Author and Affiliation Lines
Shatakshi Gupta and Randy H. Ewoldt
Mechanical Science and Engineering, University Of Illinois Urbana-champaign, Urbana, IL 61801
Speaker / Presenter
Gupta, Shatakshi
Keywords
experimental methods; theoretical methods; applied rheology; future of rheology; geoscience; industrial applications; methods; non-Newtonian fluids; rheometry; techniques
Text of Abstract
The Marsh funnel [1] is an incredibly useful test standard, a type of protorheology test [2], to infer fluid rheology (yield stress, viscosity) by observing gravity-driven discharge from a funnel. However, corrupt data and practical limitations can cause data misinterpretation, an issue in both protorheology [3] and rheometry more generally [4], and a quantitative framework to address these limits is lacking. In this work, we derive explicit limit equations for yield stress fluid tests with funnel viscometers (Marsh Funnel and other standard geometries) based on non-idealities due to fill height and stagnation height resolution, discharge time, fluid inertia, assumptions of laminar, fully developed flow, and negligible surface tension effects. These equations help identify an “operational window” on material function plots (e.g., viscosity vs stress) informing where working equation assumptions are valid. While previous studies reported fewer limitations for specific funnels, we derive general and extensive equations dependent on funnel geometry and fluid properties. Inversely, this provides an opportunity to design new funnel geometries to extend the measurement range of existing standard funnels (e.g., yield stress of 12 – 50 Pa) to practical applications like drilling and construction which encounter a wider range of rheology (e.g., yield stress of 5-100 Pa). We propose quantitative insights for designing new funnel geometries to achieve specific rheological targets, enabling broader applications of these tests.
[1] Marsh, Trans AIME (1931). DOI: 10.2118/931234-G
[2] Hossain and Ewoldt, J Rheol (2024). DOI: 10.1122/8.0000667
[3] Hossain, Tiwari, and Ewoldt, Curr Opin Colloid Interface Sci (2024). DOI: 10.1016/j.cocis.2024.101866
[4] Ewoldt, Johnston, and Caretta, in Complex Fluids in Biological Systems (2015). DOI: 10.1007/978-1-4939-2065-5_6