Calculating Maximum Dive Depth: Tips for Cliff Divers | Get the Facts Here!

  • Context: Undergrad 
  • Thread starter Thread starter Charles123
  • Start date Start date
  • Tags Tags
    Depth Maximum
Click For Summary

Discussion Overview

The discussion revolves around calculating the maximum depth a diver can reach when entering water from a height, specifically in the context of cliff diving. Participants explore various factors affecting depth, including buoyancy, drag, and the diver's position upon entry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the calculation of maximum dive depth while maintaining the same position upon water entry and not attempting to slow down.
  • Another participant suggests using kinematics to estimate depth, assuming negligible drag and losses upon entering the water, and asks if a specific scenario is being considered.
  • A participant shares a personal anecdote about being negatively buoyant as a child, indicating variability in buoyancy experiences.
  • It is noted that a diver becomes negatively buoyant as lung air compresses, typically at depths of two to three meters, after which they would continue to sink, which is relevant for free divers.
  • One participant proposes a theoretical approach equating kinetic energy with buoyant force and depth, while acknowledging that energy losses would result in a shallower depth than calculated.
  • Another participant emphasizes that buoyant force is not constant due to body compression at depth and highlights the importance of hydrodynamic resistance, suggesting that both forces need to be considered in calculations.

Areas of Agreement / Disagreement

Participants express differing views on the factors influencing dive depth, including buoyancy behavior and hydrodynamic resistance. There is no consensus on a definitive method for calculating maximum depth, and multiple competing perspectives are presented.

Contextual Notes

Participants mention complexities such as the variability of buoyant force with depth and the influence of entry technique on hydrodynamic resistance, indicating that assumptions may affect calculations.

Who May Find This Useful

This discussion may be of interest to individuals exploring physics concepts related to fluid dynamics, buoyancy, and the mechanics of diving, as well as those involved in sports science or recreational diving.

Charles123
Messages
131
Reaction score
0
How can one calculate the maximum depth a diver (jumping to water, like cliff diving) reaches if he stays in the same position that he used when entering the water, and does nothing to stop more quickly?
Thank you
Regards
 
Physics news on Phys.org
Back-of-envelope ... the diver has an initial velocity and a bouyancy: use kinematics.
Assumes negligible drag and no losses entering the water.

Fuid models can get as complicated as you need them. Did you have a particular situation in mind?
 
Once a diver has reached a particular depth, he/she will become negatively buoyant as the air in the lungs is compressed. For most people, this depth will only be two or three metres, max. After that depth, they would just keep sinking (a very handy fact for free divers).
The question would apply for an object which was incompressible and streamlined. In that case you could equate the Kinetic Energy with FD where F is the bouyancy force and D is the depth reached. But there would always be some energy losses so the depth would be less than this calculation would suggest.
 
sophiecentaur said:
Once a diver has reached a particular depth, he/she will become negatively buoyant as the air in the lungs is compressed. For most people, this depth will only be two or three metres, max. After that depth, they would just keep sinking (a very handy fact for free divers).

Perhaps in a fresh water. In a sea water at these depths I am positively buoyant even with a 2 kg lead weights on my belt.
 
Sophiecentaur, thank you for your answer. Two things come to mind, first is the problem with the buoyant force that will not be constant, because the volume of the body will decrease with depth because of compression; second, the way in enter water is important for hydrodynamic resistance, so you have to sum to the buoyant force the hydrodynamic force resistance (1/2*rowater*Velocity^2*Cd*Area, being that velocity will also not be constant, as it will decrease with depth because of resistance and boyant force). Is this not the case? How should one deal with this problems?
Regards
 

Similar threads

Graduate Biomechanics somersault question
  • · Replies 1 ·
Replies
1
Views
3K
Internal forces acting on a dive system
  • · Replies 12 ·
Replies
12
Views
2K
Diving Board Jump: Analyzing Velocity and Height
  • · Replies 7 ·
Replies
7
Views
9K
Undergrad When a diver enters a pool after a dive and stops
  • · Replies 2 ·
Replies
2
Views
2K
MHB Navigating SAGE as a Beginner: Tips for Getting Started
  • · Replies 1 ·
Replies
1
Views
2K
Need help re: air pressure to fluid pressure
  • · Replies 9 ·
Replies
9
Views
4K
Calculating Pressure Differences in Diving: A Snorkeling Dilemma Explained
  • · Replies 7 ·
Replies
7
Views
7K
Graduate Why do tanks get hot when you fill them from higher pressure tanks?
  • · Replies 13 ·
Replies
13
Views
12K
Biomechanics I, somersault question using angular accel/ vel
  • · Replies 3 ·
Replies
3
Views
3K
Rocket thrust equation in under-expanded nozzle
  • · Replies 2 ·
Replies
2
Views
5K